System Instructions
This prompt is divided into three sections:
- System Instructions (this section) — structural orientation only. Do not treat this
section as task input.
- Input Context — begins with the heading
# Input Context. All blocks are wrapped in
<pblock> tags. Two block types:
- File blocks:
<pblock filename="<name>" role="<role>" guidance="...">— optional
guidance attribute carries context-specific instructions; content is in a fenced block.
- Metadata/section blocks:
<pblock label="<label>" kind="<kind>">— job parameters,
rules, instructions, or group headers.
- Agent Task — begins with the heading
# Agent Task. Defines your persona, constraints,
and required outputs. Read all input context before acting on this section.
Input Context
<pblock label="Build block job" kind="job">
Build block job
- TARGET: jq
- BUILD_DIRECTORY: /mnt/c/Users/barlo/projects/drydock/uat/jq/runs/20260822.044627/build/jq
- WORKING_DIRECTORY: /mnt/c/Users/barlo/projects/drydock/uat/jq/runs/20260822.044627/build/jq
- BUILD_BLOCK: Block 21 · Service (block-21)
- STORIES: Implement reductions and iteration controls. (FLOW-005)
- DATE: 2026-08-22
- BUILD_SCOPE: exactly one MANIFEST.md build block
</pblock>
<pblock label="Stories in this block" kind="section">
Stories in this block
- Implement reductions and iteration controls. (FLOW-005) [story]
</pblock>
<pblock label="Files on disk" kind="section">
Files on disk in the build directory
- sources/builtin.jq
- sources/exclusions.txt
- sources/full_test.sh
- sources/jq-manual.txt
- sources/jq.test
- sources/lexer.l
- sources/parser.y
- sources/run_conformance.py
These are the only imported files present on disk. Every other file named in this prompt is supplied as prompt context and is not on disk; read it here and do not report it as a missing input.
</pblock>
COMPASS - Target Orientation
<pblock filename="COMPASS.md" role="compass" path="/mnt/c/Users/barlo/projects/drydock/uat/jq/runs/20260822.044627/workspace/targets/jq/COMPASS.md" guidance="Important: This is the core project intent, constraints, and guardrails. It should have presecedence in conflicts.">
# COMPASS: jq
## Compass
Build a standalone interpreter for the jq language as described in `sources/jq-manual.txt`. The
product is an executable file named `jq` at the application root. It reads JSON from standard
input, evaluates a jq filter as an ordered generator, and writes each value the filter produces to
standard output as one compact JSON value per line.
Correctness is measured by the upstream jq conformance corpus `sources/jq.test`, taken verbatim
from jq 1.8.2, minus the cases named in `sources/exclusions.txt`. The goal is every case passing,
none failed and none errored.
## Constraints
- Implement in Python using only the standard library.
- Provide an executable named `jq` at the application root, invoked as `./jq -c '<program>'`.
- `-c` is the only option exercised. No other command-line option is required.
- Run without network access, package installation, or external runtime dependencies.
- Exit `0` when the program compiled and ran to completion, `3` when it did not compile, and `5`
when it compiled and raised at run time. The harness grades on this distinction.
- Diagnostics go to standard error and are never compared.
## Guardrails
- Do not shell out to a system `jq` executable.
- Do not use a third-party jq implementation or binding.
- Do not modify, rewrite, trim, regenerate, or substitute any file under `sources/`. Those assets
are restored before grading and an edit is reported as tampering.
- Preserve generator ordering, multiplicity, backtracking, and partial-output runtime behavior.
- Keep compile failures distinct from runtime failures using exit codes 3 and 5.
## Verification Protocol
This section is normative. It governs which story may invoke the supplied harness, and how.
### Invoking the harness
`sources/run_conformance.py` **requires** the environment variable `JQ`, the command that runs the
candidate implementation. Without it the harness exits `2` on its own usage code, which is a
harness fault and never a verdict about the interpreter. Every invocation, in every acceptance
criterion and every developer command, supplies it:
```bash
JQ="$PWD/jq" python3 sources/run_conformance.py # whole corpus, the scored run
JQ="$PWD/jq" python3 sources/run_conformance.py --select 'reduce' # run one construct for real
```
Those two commands are the only ways this build runs the harness. They are specified verbatim
below under *The two harness invocations*, together with the flag this build forbids.
`sources/` is read only. No story edits, patches, or regenerates `sources/run_conformance.py`,
`sources/jq.test`, or `sources/exclusions.txt`; a harness defect is reported, not repaired in
place. A story that needs to experiment with the harness works on a copy outside `sources/`, and
every acceptance criterion invokes the original `sources/run_conformance.py`.
An acceptance criterion written in Python supplies it by **extending** the inherited environment,
never by replacing it:
```python
env={**os.environ, "JQ": str(build_dir / "jq")}
```
`env={"JQ": ...}` alone leaves the child with no `PATH`, so nothing it invokes resolves and the
criterion is false at every level of implementation quality.
`sources/full_test.sh` sets `JQ` itself for the runner it wraps and therefore takes no environment
from its caller.
The harness reserves exit `2` for its own faults — a missing corpus, an unset `JQ`, a stale
exclusion list. Exit `2` never means the interpreter is wrong.
The summary line is:
```
jq conformance: NNN passed, N failed, N errored, N skipped (corpus jq.test @ jq-1.8.2)
```
### The two harness invocations
An acceptance criterion that runs `sources/run_conformance.py` uses one of these two commands. No
criterion in this build passes any other flag to the harness.
| Story kind | Command | Executes cases? | Asserts |
|---|---|---|---|
| Every behavioral story | `--select <regex> --json` | Yes, the selected slice | exit `0`, zero `fail`, zero `error`, non-zero case count |
| Terminal story (once, last) | `sh sources/full_test.sh` | Yes, all of them | exit `0` |
The staging story does not appear in this table. It does not run the harness at all; see *The
staging story* below.
#### `--list` is never run
`sources/run_conformance.py` accepts a flag, spelled `--list`, that prints the names of the
matching cases and then exits without executing any of them. `sources/INSTRUCTIONS.md`, the file
header, and `--help` all document it.
**This build never runs it. Not in an acceptance criterion, not in a story, not in a script, not
in a command typed by a build agent, not while developing and not while verifying. The string
`--list` does not appear anywhere in this project's output. If you have written it, that line is
wrong — delete it and use one of the two commands above.**
A Drydock build is headless. There is no one watching the output, so a mode whose entire purpose
is to print something for a person to read has no reader and no reason to run.
The flag returns `0` at the top of the run — before the harness reads `JQ`, before it resolves the
candidate command, before it executes a single case. A criterion built on it passes when `jq` is
an empty file, when `jq` does not exist, and when the story it gates was never written. It is not
a weak proof, not a partial proof, and not an acceptable proof for staging, for scaffolding, or
for an early story whose implementation is incomplete. It is not a proof. Thirty-six criteria in
one earlier plan of this project used it, every one of them reported green, and it cost three days.
If you are writing a criterion and reaching for that flag, the reason is always the same: the
story's code does not exist yet and you want a command that will not fail. That is the definition
of a criterion that proves nothing. Write the `--select ... --json` form instead and let it be red
until the story makes it green. **A criterion is supposed to fail before its story is built.**
The same prohibition covers any other flag whose effect is to not execute the cases — enumeration,
dry-run, validation, or help. If a flag's documented purpose is "run nothing", it has no place in
an acceptance criterion.
#### Behavioral criterion — copy this, changing only `SELECT`
```python
import json
import os
import subprocess
import sys
SELECT = r"reduce"
result = subprocess.run(
[sys.executable, "sources/run_conformance.py", "--select", SELECT, "--json"],
capture_output=True,
text=True,
env={**os.environ, "JQ": f"{os.getcwd()}/jq"},
)
print(result.stdout)
print(result.stderr, file=sys.stderr)
report = json.loads(result.stdout)
tally = report["summary"]
assert sum(tally.values()) > 0, f"selector matched no case: {SELECT}"
assert tally["fail"] == 0 and tally["error"] == 0, tally
assert result.returncode == 0, result.returncode
```
Three assertions, and all three are required.
1. **The selector matched something.** `--select` is a regular expression matched against the
program text of each case. A selector that matches nothing yields zero cases, zero failures,
and exit `0` — green, and worth nothing. Alternations naming ideas rather than syntax
(`closure`, `recursive`, `optional`) match no jq program and are the common way to write one
by accident. Select on syntax the corpus actually contains: `reduce`, `foreach`, `def `,
` as \$`, `try `, `//`, `path(`.
2. **No case failed or errored.** Read off the parsed JSON tally, not off any printed line.
3. **The exit status is `0`.** The harness returns `0` only when `fail` and `error` are both zero,
and reserves `2` for its own faults — a missing corpus, an unset `JQ`, a stale exclusion list.
Exit `2` is never a verdict about the interpreter.
`--json` writes the report and nothing else to stdout, so `json.loads(result.stdout)` is total. Do
not assert against the human summary line, and do not grep stdout for `passed` or `failed`.
### The terminal story
The **terminal story** is the last story in the build order: the one on which every other story is
a transitive dependency, and after which no further story runs. It is a verification story. Its
job is not to add capability but to prove that the capability every preceding story delivered is
present, together, at the end of the build.
The terminal story of this project runs `sh sources/full_test.sh`, asserts `returncode == 0`,
prints the captured stdout and stderr so a failure is diagnosable from the evidence alone, and
carries the Sea Trial. It is the only story permitted to run the whole corpus.
A story is not terminal because its name contains "verify", because it is a test harness, or
because it stages the test assets. Staging the corpus is foundational work that happens early;
running the corpus is terminal work that happens last. Do not place a whole-corpus gate on a
story that cannot yet run it — it fails vacuously and teaches nothing.
### Scope of every other story
Every non-terminal story is gated on its own declared behavior only, through `--select` against
the constructs that story implements, and the criterion asserts the selected slice passes. A
non-terminal story never invokes `sources/full_test.sh` and never runs the corpus unfiltered: a
partial interpreter fails most of an authoritative corpus by construction, and its unimplemented
cases exhaust the harness's per-case timeout rather than returning, so the unscoped run costs the
most exactly where it teaches the least.
Regression across stories is not the responsibility of any story's criteria. Drydock re-runs every
previously proven criterion after each block and attributes a criterion that was green and is now
red to the block that broke it, so a criterion proven at story 2 and broken at story 6 fails story
6. Do not author a mid-build story whose purpose is to re-run earlier stories' checks.
### The staging story
The story that stages the conformance assets is gated on the assets being present, complete, and
mutually consistent — not on a bare file-existence assertion, and not on the corpus running. It
proves that in process, by importing the harness and calling its parsers directly. It never
launches the harness, so the question of which flags to pass does not arise:
```python
import sys
sys.path.insert(0, "sources")
import run_conformance as harness
EXPECTED_CASES = 550
EXPECTED_EXCLUSIONS = 13
cases = harness.parse_corpus(harness.CORPUS.read_text(encoding="utf-8"))
excluded = harness.apply_exclusions(cases, harness.parse_exclusions(harness.EXCLUSIONS))
assert len(cases) == EXPECTED_CASES, len(cases)
assert len(excluded) == EXPECTED_EXCLUSIONS, len(excluded)
```
This reads state rather than output: the harness module imports, the corpus parses into the
expected number of cases, and every exclusion still matches a case — `apply_exclusions` raises on
a stale entry, so a corpus and an exclusion list that have drifted apart fail here rather than
silently skipping cases later.
It claims nothing about the interpreter, because at this point in the build there is nothing to
claim. Every story that claims a construct works runs that construct through
`--select ... --json`.
## The corpus
`sources/jq.test` documents its own format in its header. Cases are separated by blank lines;
blank lines and `#` lines are ignored. A case is a program line, an input line, and then the
expected output values, one per line. A case preceded by `%%FAIL` is a program that must be
rejected at compile time; the following lines are upstream jq's diagnostic, which the harness
records but never compares. Reproducing jq's exact error text is reverse-engineering a C
implementation rather than conforming to a specification, so a `%%FAIL` case passes on exit `3`
alone.
Values are compared structurally, not textually. `1` and `1.0` are the same jq value, and so are
two objects whose keys print in a different order. Output formatting is therefore not under test,
but the number and order of values is.
`sources/exclusions.txt` names the corpus cases this kit cannot run, with the reason. They are the
module-loader cases, whose `import` and `include` resolve against a search path of fixture files a
flat source import cannot carry. They are reported as `skipped` and are not part of the score.
The module *grammar* cases are not excluded and must pass. `module (.+1); 0`, `module []; 0`,
`include "a" (.+1); 0`, `include "a" []; 0`, `include "\ "; 0`, `include "\(a)"; 0`, and `%::wat`
are all `%%FAIL` cases: the front end parses the module syntax far enough to reject them, without
ever touching the filesystem.
<!-- drydock:build-write-guardrail:start -->
## Build Write Guardrail
- Authorized build directory: `/mnt/c/Users/barlo/projects/drydock/uat/jq/runs/20260822.044627/build/jq`
- Authorized Target directory: `/mnt/c/Users/barlo/projects/drydock/uat/jq/runs/20260822.044627/workspace/targets/jq`
- Build agents have permission to create, modify, and remove files required by the active build block inside these authorized directories.
- No path outside these authorized directories may be modified.
- Protected Drydock artifacts:
- `/mnt/c/Users/barlo/projects/drydock/uat/jq/runs/20260822.044627/workspace/targets/jq/blueprint/`
- `/mnt/c/Users/barlo/projects/drydock/uat/jq/runs/20260822.044627/workspace/targets/jq/MANIFEST.md`
- `/mnt/c/Users/barlo/projects/drydock/uat/jq/runs/20260822.044627/workspace/targets/jq/COMPASS.md`
- `/mnt/c/Users/barlo/projects/drydock/uat/jq/runs/20260822.044627/workspace/targets/jq/QuarterDeck/`
- `/mnt/c/Users/barlo/projects/drydock/uat/jq/runs/20260822.044627/workspace/targets/jq/evidence/`
<!-- drydock:build-write-guardrail:end --></pblock>
STACK - Technology HOW
<pblock filename="python_compact.md" role="stack" path="/mnt/c/Users/barlo/projects/drydock/Rigging/stack/python_compact.md">
<!-- Compacted from rigging/stack/python.md on 2026-07-16 (manual update to match python.md V3) -->
# Python — Compact
## Configuration Management
One typed frozen-dataclass `Config` is the only env reader — never read `os.environ` elsewhere. No `Dev`/`Prod`/`Test` subclasses; the environment (`.env`) selects configuration. Never hardcode secrets, ports, or paths. Secret hygiene and `.env.example`: see `stack/env_variables_and_secrets.md`.
```python
# config.py
import os
from dataclasses import dataclass
from dotenv import load_dotenv
load_dotenv()
@dataclass(frozen=True)
class Config:
secret_key: str
database_path: str
port: int
debug: bool = False
@classmethod
def load(cls) -> "Config":
try:
return cls(
secret_key=os.environ["SECRET_KEY"],
database_path=os.environ.get("DATABASE_PATH", "data/app.db"),
port=int(os.environ.get("APP_PORT", "5001")),
debug=os.environ.get("APP_DEBUG") == "1",
)
except KeyError as e:
raise RuntimeError(f"Missing required env var: {e}") from e
```
## Code Style and Understandability
Code must be understandable through naming, structure, small focused units, explicit types, clear interfaces, appropriate abstractions, and tests. Names state intent; one responsibility per module; functions do one thing at one level of abstraction; no speculative abstraction layers. Comments state constraints the code cannot express — never restate mechanics.
## Type Hints and Static Typing
Modern hints on all public interfaces; typed structures across boundaries; run a type checker when practical.
- Built-in generics (`list[str]`, `dict[str, int]`) and `X | None` — never `typing.List`, `Optional`, `Union`
- Type every public function, method, and class attribute
- Schemas/serializers/services/data structures are typed classes: frozen dataclasses internally, Pydantic/`TypedDict` at serialization boundaries
- No bare `dict`, positional tuples, or `Any` crossing a module boundary
- `uv add --dev mypy` then `uv run mypy .` (or pyright) alongside ruff and pytest in CI
## Logging
Use `logging` with named loggers, never `print()`. Configure formatter + console and file handlers at startup (`data/logs/app.log`); level from `APP_DEBUG`.
```python
import logging
logger = logging.getLogger(__name__)
logger.info('Server starting on port %s', port)
```
## Environment Separation
Distinct `.env` per environment; same typed `Config` reads whichever is present. Never run debug in production.
| Setting | Dev | Test | Prod |
|---------|-----|------|------|
| APP_DEBUG | 1 | 0 | 0 |
| DATABASE_PATH | data/app.db | :memory: | data/app.db |
| SECRET_KEY | .env value | .env value | .env value (required) |
| LOGGING | DEBUG | WARNING | INFO |
## Testing
`pytest` with fixtures; fresh in-memory DB per test; test at the boundary. Every Python build must include a complete pytest suite regardless of the specification — no tests, no ACTIVE conformity.
```python
# tests/conftest.py
import pytest
@pytest.fixture
def app(monkeypatch):
monkeypatch.setenv("SECRET_KEY", "test")
monkeypatch.setenv("DATABASE_PATH", ":memory:")
from app import create_app
from config import Config
yield create_app(Config.load())
@pytest.fixture
def client(app):
return app.test_client()
```
**test_smoke.py** — app factory works; `GET /health` returns 200 `{"status": "ok"}`; `GET /` returns 200.
**test_routes.py** — one test per route: `GET` pages assert 200; `POST` APIs assert status in `{200, 201, 204}`; HTMX routes send `HX-Request: true`; `{id}` routes use fixture-created records.
**test_db.py** (only if DATABASE.md exists) — expected tables exist; round-trip per major table; invalid FK raises `IntegrityError` (`PRAGMA foreign_keys=ON`).
Do not test third-party internals, config loading, or private helpers.
```ini
# pytest.ini
[pytest]
testpaths = tests
addopts = -v
```
## Security
Validate all user input; parameterized queries exclusively; never trust client data.
- `?` placeholders, never f-strings, for all DB operations
- `secure_filename()` for user-supplied paths
- Length and type validation on inputs
- Secret key from environment, never hardcoded
- Never expose stack traces to end users
## Dependency Management (uv)
`uv` only; `pyproject.toml` is the manifest; `uv.lock` committed; `.venv/` gitignored. Full toolchain conventions: `stack/uv_ruff.md`.
```bash
uv venv # creates .venv/
uv add flask python-dotenv # runtime deps → pyproject.toml + uv.lock
uv add --dev pytest ruff mypy # dev deps
uv sync --frozen # CI — fail if lock is stale
```
- Never bare `pip install` or `python -m venv`
- Dev deps in `[project.optional-dependencies].dev`; runtime deps minimal
## Startup Validation
`Config.load()` already validates required env vars; startup validation confirms DB connectivity. Crash early on misconfiguration.
```python
def validate_startup(config: Config, db: Database):
try:
db.healthcheck() # SELECT 1 inside the Database class
except Exception as e:
raise RuntimeError(f'Database not accessible: {e}')
logger.info('Startup validation passed')
```
## Directory Layout
```
project-name/
├── app.py # Entry point / app factory
├── routes.py # Route handlers
├── models.py # Data models and type registries
├── db.py # Database class: typed tables, connection, schema, migrations
├── ops.py # Business logic and operations
├── config.py # typed Config class — the only env reader
├── templates/ # base.html + types/ partials
├── static/ # css/, js/
├── tests/ # conftest.py, test_*.py
├── bin/ # (from common.md)
├── data/ # (from common.md)
├── pyproject.toml
├── uv.lock
├── .env # gitignored; .env.example committed
└── .gitignore
```</pblock>
CONTEXT - Read-Only Support
<pblock filename="builtin.jq" role="context" path="/mnt/c/Users/barlo/projects/drydock/uat/jq/runs/20260822.044627/workspace/targets/jq/blueprint/builtin.jq">
def halt_error: halt_error(5);
def error(msg): msg|error;
def map(f): [.[] | f];
def select(f): if f then . else empty end;
def sort_by(f): _sort_by_impl(map([f]));
def group_by(f): _group_by_impl(map([f]));
def unique_by(f): _unique_by_impl(map([f]));
def max_by(f): _max_by_impl(map([f]));
def min_by(f): _min_by_impl(map([f]));
def add(f): reduce f as $x (null; . + $x);
def add: add(.[]);
def del(f): delpaths([path(f)]);
def abs: if . < 0 then - . else . end;
def _assign(paths; $value): reduce path(paths) as $p (.; setpath($p; $value));
def _modify(paths; update):
reduce path(paths) as $p ([., []];
. as $dot
| null
| label $out
| ($dot[0] | getpath($p)) as $v
| (
( $$$$v
| update
| (., break $out) as $v
| $$$$dot
| setpath([0] + $p; $v)
),
(
$$$$dot
| setpath([1, (.[1] | length)]; $p)
)
)
) | . as $dot | $dot[0] | delpaths($dot[1]);
def map_values(f): .[] |= f;
# recurse
def recurse(f): def r: ., (f | r); r;
def recurse(f; cond): def r: ., (f | select(cond) | r); r;
def recurse: recurse(.[]?);
def to_entries: [keys_unsorted[] as $k | {key: $k, value: .[$k]}];
def from_entries: map({ (.key // .Key // .name // .Name):
if has("value") then .value else .Value end }) | add // {};
def with_entries(f): to_entries | map(f) | from_entries;
def reverse: [.[length - 1 - range(0;length)]];
def indices($i): if type == "array" and ($i|type) == "array" then .[$i]
elif type == "array" then .[[$i]]
elif type == "string" and ($i|type) == "string" then _strindices($i)
else .[$i] end;
def index($i): indices($i) | .[0]; # TODO: optimize
def rindex($i): indices($i) | .[-1:][0]; # TODO: optimize
def paths: path(recurse)|select(length > 0);
def paths(node_filter): path(recurse|select(node_filter))|select(length > 0);
def isfinite: type == "number" and (isinfinite | not);
def arrays: select(type == "array");
def objects: select(type == "object");
def iterables: select(type|. == "array" or . == "object");
def booleans: select(type == "boolean");
def numbers: select(type == "number");
def normals: select(isnormal);
def finites: select(isfinite);
def strings: select(type == "string");
def nulls: select(. == null);
def values: select(. != null);
def scalars: select(type|. != "array" and . != "object");
def join($x): reduce .[] as $i (null;
(if .==null then "" else .+$x end) +
($i | if type=="boolean" or type=="number" then tostring else .//"" end)
) // "";
def _flatten($x): reduce .[] as $i ([]; if $i | type == "array" and $x != 0 then . + ($i | _flatten($x-1)) else . + [$i] end);
def flatten($x): if $x < 0 then error("flatten depth must not be negative") else _flatten($x) end;
def flatten: _flatten(-1);
def range($x): range(0;$x);
def fromdateiso8601: strptime("%Y-%m-%dT%H:%M:%SZ")|mktime;
def todateiso8601: strftime("%Y-%m-%dT%H:%M:%SZ");
def fromdate: fromdateiso8601;
def todate: todateiso8601;
def ltrimstr($left): if startswith($left) then .[$left | length:] end;
def rtrimstr($right): if endswith($right) then .[:length - ($right | length)] end;
def trimstr($val): ltrimstr($val) | rtrimstr($val);
def match(re; mode): _match_impl(re; mode; false)|.[];
def match($val): ($val|type) as $vt | if $vt == "string" then match($val; null)
elif $vt == "array" and ($val | length) > 1 then match($val[0]; $val[1])
elif $vt == "array" and ($val | length) > 0 then match($val[0]; null)
else error( $vt + " not a string or array") end;
def test(re; mode): _match_impl(re; mode; true);
def test($val): ($val|type) as $vt | if $vt == "string" then test($val; null)
elif $vt == "array" and ($val | length) > 1 then test($val[0]; $val[1])
elif $vt == "array" and ($val | length) > 0 then test($val[0]; null)
else error( $vt + " not a string or array") end;
def capture(re; mods): match(re; mods) | reduce ( .captures | .[] | select(.name != null) | { (.name) : .string } ) as $pair ({}; . + $pair);
def capture($val): ($val|type) as $vt | if $vt == "string" then capture($val; null)
elif $vt == "array" and ($val | length) > 1 then capture($val[0]; $val[1])
elif $vt == "array" and ($val | length) > 0 then capture($val[0]; null)
else error( $vt + " not a string or array") end;
def scan($re; $flags):
match($re; "g" + $flags)
| if (.captures|length > 0)
then [ .captures | .[] | .string ]
else .string
end;
def scan($re): scan($re; null);
# splits/1 produces a stream; split/1 is retained for backward compatibility.
def splits($re; $flags):
.[foreach (match($re; $flags+"g"), null) as {$offset, $length}
(null; {start: .next, end: $offset, next: ($offset+$length)})];
def splits($re): splits($re; null);
# split emits an array for backward compatibility
def split($re; $flags): [ splits($re; $flags) ];
# If s contains capture variables, then create a capture object and pipe it to s, bearing
# in mind that s could be a stream
def sub($re; s; $flags):
. as $in
| (reduce match($re; $flags) as $edit
({result: [], previous: 0};
$in[ .previous: ($edit | .offset) ] as $gap
# create the "capture" objects (one per item in s)
| [reduce ( $edit | .captures | .[] | select(.name != null) | { (.name) : .string } ) as $pair
({}; . + $pair) | s ] as $inserts
| reduce range(0; $inserts|length) as $ix (.; .result[$ix] += $gap + $inserts[$ix])
| .previous = ($edit | .offset + .length ) )
| .result[] + $in[.previous:] )
// $in;
def sub($re; s): sub($re; s; "");
def gsub($re; s; flags): sub($re; s; flags + "g");
def gsub($re; s): sub($re; s; "g");
########################################################################
# generic iterator/generator
def while(cond; update):
def _while:
if cond then ., (update | _while) else empty end;
_while;
def until(cond; next):
def _until:
if cond then . else (next|_until) end;
_until;
def limit($n; expr):
if $n > 0 then label $out | foreach expr as $item ($n; . - 1; $item, if . <= 0 then break $out else empty end)
elif $n == 0 then empty
else error("limit doesn't support negative count") end;
def skip($n; expr):
if $n > 0 then foreach expr as $item ($n; . - 1; if . < 0 then $item else empty end)
elif $n == 0 then expr
else error("skip doesn't support negative count") end;
# range/3, with a `by` expression argument
def range($init; $upto; $by):
if $by > 0 then $init|while(. < $upto; . + $by)
elif $by < 0 then $init|while(. > $upto; . + $by)
else empty end;
def first(g): label $out | g | ., break $out;
def isempty(g): first((g|false), true);
def all(generator; condition): isempty(generator|condition and empty);
def any(generator; condition): isempty(generator|condition or empty)|not;
def all(condition): all(.[]; condition);
def any(condition): any(.[]; condition);
def all: all(.[]; .);
def any: any(.[]; .);
def nth($n; g):
if $n < 0 then error("nth doesn't support negative indices")
else first(skip($n; g)) end;
def first: .[0];
def last: .[-1];
def nth($n): .[$n];
def combinations:
if length == 0 then [] else
.[0][] as $x
| (.[1:] | combinations) as $y
| [$x] + $y
end;
def combinations(n):
. as $dot
| [range(n) | $dot]
| combinations;
# transpose a possibly jagged matrix, quickly;
# rows are padded with nulls so the result is always rectangular.
def transpose: [range(0; map(length)|max // 0) as $i | [.[][$i]]];
def in(xs): . as $x | xs | has($x);
def inside(xs): . as $x | xs | contains($x);
def repeat(exp):
def _repeat:
exp, _repeat;
_repeat;
def inputs: try repeat(input) catch if .=="break" then empty else error end;
# like ruby's downcase - only characters A to Z are affected
def ascii_downcase:
explode | map( if 65 <= . and . <= 90 then . + 32 else . end) | implode;
# like ruby's upcase - only characters a to z are affected
def ascii_upcase:
explode | map( if 97 <= . and . <= 122 then . - 32 else . end) | implode;
# Streaming utilities
def truncate_stream(stream):
. as $n | null | stream | . as $input | if (.[0]|length) > $n then setpath([0];$input[0][$n:]) else empty end;
def fromstream(i): {x: null, e: false} as $init |
# .x = object being built; .e = emit and reset state
foreach i as $i ($init
; if .e then $init else . end
| if $i|length == 2
then setpath(["e"]; $i[0]|length==0) | setpath(["x"]+$i[0]; $i[1])
else setpath(["e"]; $i[0]|length==1) end
; if .e then .x else empty end);
def tostream:
path(def r: (.[]?|r), .; r) as $p |
getpath($p) |
reduce path(.[]?) as $q ([$p, .]; [$p+$q]);
# Apply f to composite entities recursively, and to atoms
def walk(f):
def w:
if type == "object"
then map_values(w)
elif type == "array" then map(w)
else .
end
| f;
w;
# pathexps could be a stream of dot-paths
def pick(pathexps):
. as $in
| reduce path(pathexps) as $a (null;
setpath($a; $in|getpath($a)) );
# ensure the output of debug(m1,m2) is kept together:
def debug(msgs): (msgs | debug | empty), .;
# SQL-ish operators here:
def INDEX(stream; idx_expr):
reduce stream as $row ({}; .[$row|idx_expr|tostring] = $row);
def INDEX(idx_expr): INDEX(.[]; idx_expr);
def JOIN($idx; idx_expr):
[.[] | [., $idx[idx_expr]]];
def JOIN($idx; stream; idx_expr):
stream | [., $idx[idx_expr]];
def JOIN($idx; stream; idx_expr; join_expr):
stream | [., $idx[idx_expr]] | join_expr;
def IN(s): any(s == .; .);
def IN(src; s): any(src == s; .);</pblock>
<pblock filename="jq-manual.txt" role="context" path="/mnt/c/Users/barlo/projects/drydock/uat/jq/runs/20260822.044627/workspace/targets/jq/blueprint/jq-manual.txt">
The jq Language Manual
======================
Rendered from the jq manual at tag jq-1.8.2 (docs/content/manual/v1.8/manual.yml).
See PROVENANCE.md for the upstream hash.
This is the normative description of the jq language and is the primary specification
for this project. Section and entry titles, prose, and worked examples are upstream's,
verbatim and in document order. The manual's "Invoking jq" and "Colors" sections are
omitted: they describe jq's command-line option surface, which this project does not
implement and the conformance corpus does not exercise.
Worked examples read:
Example: <the jq program>
Input: <the JSON input>
Output: <each JSON value the program produces, one per line>
Introduction
------------
A jq program is a "filter": it takes an input, and produces an
output. There are a lot of builtin filters for extracting a
particular field of an object, or converting a number to a string,
or various other standard tasks.
Filters can be combined in various ways - you can pipe the output of
one filter into another filter, or collect the output of a filter
into an array.
Some filters produce multiple results, for instance there's one that
produces all the elements of its input array. Piping that filter
into a second runs the second filter for each element of the
array. Generally, things that would be done with loops and iteration
in other languages are just done by gluing filters together in jq.
It's important to remember that every filter has an input and an
output. Even literals like "hello" or 42 are filters - they take an
input but always produce the same literal as output. Operations that
combine two filters, like addition, generally feed the same input to
both and combine the results. So, you can implement an averaging
filter as `add / length` - feeding the input array both to the `add`
filter and the `length` filter and then performing the division.
But that's getting ahead of ourselves. :) Let's start with something
simpler:
============================================================================
SECTION: Basic filters
============================================================================
----------------------------------------------------------------------------
Identity: `.`
----------------------------------------------------------------------------
The absolute simplest filter is `.` . This filter takes its
input and produces the same value as output. That is, this
is the identity operator.
Since jq by default pretty-prints all output, a trivial
program consisting of nothing but `.` can be used to format
JSON output from, say, `curl`.
Although the identity filter never modifies the value of its
input, jq processing can sometimes make it appear as though
it does. For example, using the current implementation of
jq, we would see that the expression:
1E1234567890 | .
produces `1.7976931348623157e+308` on at least one platform.
This is because, in the process of parsing the number, this
particular version of jq has converted it to an IEEE754
double-precision representation, losing precision.
The way in which jq handles numbers has changed over time
and further changes are likely within the parameters set by
the relevant JSON standards. Moreover, build configuration
options can alter how jq processes numbers.
The following remarks are therefore offered with the
understanding that they are intended to be descriptive of the
current version of jq and should not be interpreted as being
prescriptive:
(1) Any arithmetic operation on a number that has not
already been converted to an IEEE754 double precision
representation will trigger a conversion to the IEEE754
representation.
(2) jq will attempt to maintain the original decimal
precision of number literals (if the `--disable-decnum`
build configuration option was not used), but in expressions
such `1E1234567890`, precision will be lost if the exponent
is too large.
(3) Comparisons are carried out using the untruncated
big decimal representation of numbers if available, as
illustrated in one of the following examples.
The examples below use the builtin function `have_decnum` in
order to demonstrate the expected effects of using / not
using the `--disable-decnum` build configuration option, and
also to allow automated tests derived from these examples to
pass regardless of whether that option is used.
Example: .
Input: "Hello, world!"
Output: "Hello, world!"
Example: .
Input: 0.12345678901234567890123456789
Output: 0.12345678901234567890123456789
Example: [., tojson] == if have_decnum then [12345678909876543212345,"12345678909876543212345"] else [12345678909876543000000,"12345678909876543000000"] end
Input: 12345678909876543212345
Output: true
Example: [1234567890987654321,-1234567890987654321 | tojson] == if have_decnum then ["1234567890987654321","-1234567890987654321"] else ["1234567890987654400","-1234567890987654400"] end
Input: null
Output: true
Example: . < 0.12345678901234567890123456788
Input: 0.12345678901234567890123456789
Output: false
Example: map([., . == 1]) | tojson == if have_decnum then "[[1,true],[1.000,true],[1.0,true],[1.00,true]]" else "[[1,true],[1,true],[1,true],[1,true]]" end
Input: [1, 1.000, 1.0, 100e-2]
Output: true
Example: . as $big | [$big, $big + 1] | map(. > 10000000000000000000000000000000) | . == if have_decnum then [true, false] else [false, false] end
Input: 10000000000000000000000000000001
Output: true
----------------------------------------------------------------------------
Object Identifier-Index: `.foo`, `.foo.bar`
----------------------------------------------------------------------------
The simplest *useful* filter has the form `.foo`. When given a
JSON object (aka dictionary or hash) as input, `.foo` produces
the value at the key "foo" if the key is present, or null otherwise.
A filter of the form `.foo.bar` is equivalent to `.foo | .bar`.
The `.foo` syntax only works for simple, identifier-like keys, that
is, keys that are all made of alphanumeric characters and
underscore, and which do not start with a digit.
If the key contains special characters or starts with a digit,
you need to surround it with double quotes like this:
`."foo$"`, or else `.["foo$"]`.
For example `.["foo::bar"]` and `.["foo.bar"]` work while
`.foo::bar` does not.
Example: .foo
Input: {"foo": 42, "bar": "less interesting data"}
Output: 42
Example: .foo
Input: {"notfoo": true, "alsonotfoo": false}
Output: null
Example: .["foo"]
Input: {"foo": 42}
Output: 42
----------------------------------------------------------------------------
Optional Object Identifier-Index: `.foo?`
----------------------------------------------------------------------------
Just like `.foo`, but does not output an error when `.` is not an
object.
Example: .foo?
Input: {"foo": 42, "bar": "less interesting data"}
Output: 42
Example: .foo?
Input: {"notfoo": true, "alsonotfoo": false}
Output: null
Example: .["foo"]?
Input: {"foo": 42}
Output: 42
Example: [.foo?]
Input: [1,2]
Output: []
----------------------------------------------------------------------------
Object Index: `.[<string>]`
----------------------------------------------------------------------------
You can also look up fields of an object using syntax like
`.["foo"]` (`.foo` above is a shorthand version of this, but
only for identifier-like strings).
----------------------------------------------------------------------------
Array Index: `.[<number>]`
----------------------------------------------------------------------------
When the index value is an integer, `.[<number>]` can index
arrays. Arrays are zero-based, so `.[2]` returns the third
element.
Negative indices are allowed, with -1 referring to the last
element, -2 referring to the next to last element, and so on.
Example: .[0]
Input: [{"name":"JSON", "good":true}, {"name":"XML", "good":false}]
Output: {"name":"JSON", "good":true}
Example: .[2]
Input: [{"name":"JSON", "good":true}, {"name":"XML", "good":false}]
Output: null
Example: .[-2]
Input: [1,2,3]
Output: 2
----------------------------------------------------------------------------
Array/String Slice: `.[<number>:<number>]`
----------------------------------------------------------------------------
The `.[<number>:<number>]` syntax can be used to return a
subarray of an array or substring of a string. The array
returned by `.[10:15]` will be of length 5, containing the
elements from index 10 (inclusive) to index 15 (exclusive).
Either index may be negative (in which case it counts
backwards from the end of the array), or omitted (in which
case it refers to the start or end of the array).
Indices are zero-based.
Example: .[2:4]
Input: ["a","b","c","d","e"]
Output: ["c", "d"]
Example: .[2:4]
Input: "abcdefghi"
Output: "cd"
Example: .[:3]
Input: ["a","b","c","d","e"]
Output: ["a", "b", "c"]
Example: .[-2:]
Input: ["a","b","c","d","e"]
Output: ["d", "e"]
----------------------------------------------------------------------------
Array/Object Value Iterator: `.[]`
----------------------------------------------------------------------------
If you use the `.[index]` syntax, but omit the index
entirely, it will return *all* of the elements of an
array. Running `.[]` with the input `[1,2,3]` will produce the
numbers as three separate results, rather than as a single
array. A filter of the form `.foo[]` is equivalent to
`.foo | .[]`.
You can also use this on an object, and it will return all
the values of the object.
Note that the iterator operator is a generator of values.
Example: .[]
Input: [{"name":"JSON", "good":true}, {"name":"XML", "good":false}]
Output: {"name":"JSON", "good":true}
{"name":"XML", "good":false}
Example: .[]
Input: []
Output: (no output)
Example: .foo[]
Input: {"foo":[1,2,3]}
Output: 1
2
3
Example: .[]
Input: {"a": 1, "b": 1}
Output: 1
1
----------------------------------------------------------------------------
`.[]?`
----------------------------------------------------------------------------
Like `.[]`, but no errors will be output if . is not an array
or object. A filter of the form `.foo[]?` is equivalent to
`.foo | .[]?`.
----------------------------------------------------------------------------
Comma: `,`
----------------------------------------------------------------------------
If two filters are separated by a comma, then the
same input will be fed into both and the two filters' output
value streams will be concatenated in order: first, all of the
outputs produced by the left expression, and then all of the
outputs produced by the right. For instance, filter `.foo,
.bar`, produces both the "foo" fields and "bar" fields as
separate outputs.
The `,` operator is one way to construct generators.
Example: .foo, .bar
Input: {"foo": 42, "bar": "something else", "baz": true}
Output: 42
"something else"
Example: .user, .projects[]
Input: {"user":"stedolan", "projects": ["jq", "wikiflow"]}
Output: "stedolan"
"jq"
"wikiflow"
Example: .[4,2]
Input: ["a","b","c","d","e"]
Output: "e"
"c"
----------------------------------------------------------------------------
Pipe: `|`
----------------------------------------------------------------------------
The | operator combines two filters by feeding the output(s) of
the one on the left into the input of the one on the right. It's
similar to the Unix shell's pipe, if you're used to that.
If the one on the left produces multiple results, the one on
the right will be run for each of those results. So, the
expression `.[] | .foo` retrieves the "foo" field of each
element of the input array. This is a cartesian product,
which can be surprising.
Note that `.a.b.c` is the same as `.a | .b | .c`.
Note too that `.` is the input value at the particular stage
in a "pipeline", specifically: where the `.` expression appears.
Thus `.a | . | .b` is the same as `.a.b`, as the `.` in the
middle refers to whatever value `.a` produced.
Example: .[] | .name
Input: [{"name":"JSON", "good":true}, {"name":"XML", "good":false}]
Output: "JSON"
"XML"
----------------------------------------------------------------------------
Parenthesis
----------------------------------------------------------------------------
Parenthesis work as a grouping operator just as in any typical
programming language.
Example: (. + 2) * 5
Input: 1
Output: 15
============================================================================
SECTION: Types and Values
============================================================================
jq supports the same set of datatypes as JSON - numbers,
strings, booleans, arrays, objects (which in JSON-speak are
hashes with only string keys), and "null".
Booleans, null, strings and numbers are written the same way as
in JSON. Just like everything else in jq, these simple
values take an input and produce an output - `42` is a valid jq
expression that takes an input, ignores it, and returns 42
instead.
Numbers in jq are internally represented by their IEEE754 double
precision approximation. Any arithmetic operation with numbers,
whether they are literals or results of previous filters, will
produce a double precision floating point result.
However, when parsing a literal jq will store the original literal
string. If no mutation is applied to this value then it will make
to the output in its original form, even if conversion to double
would result in a loss.
----------------------------------------------------------------------------
Array construction: `[]`
----------------------------------------------------------------------------
As in JSON, `[]` is used to construct arrays, as in
`[1,2,3]`. The elements of the arrays can be any jq
expression, including a pipeline. All of the results produced
by all of the expressions are collected into one big array.
You can use it to construct an array out of a known quantity
of values (as in `[.foo, .bar, .baz]`) or to "collect" all the
results of a filter into an array (as in `[.items[].name]`)
Once you understand the "," operator, you can look at jq's array
syntax in a different light: the expression `[1,2,3]` is not using a
built-in syntax for comma-separated arrays, but is instead applying
the `[]` operator (collect results) to the expression 1,2,3 (which
produces three different results).
If you have a filter `X` that produces four results,
then the expression `[X]` will produce a single result, an
array of four elements.
Example: [.user, .projects[]]
Input: {"user":"stedolan", "projects": ["jq", "wikiflow"]}
Output: ["stedolan", "jq", "wikiflow"]
Example: [ .[] | . * 2]
Input: [1, 2, 3]
Output: [2, 4, 6]
----------------------------------------------------------------------------
Object Construction: `{}`
----------------------------------------------------------------------------
Like JSON, `{}` is for constructing objects (aka
dictionaries or hashes), as in: `{"a": 42, "b": 17}`.
If the keys are "identifier-like", then the quotes can be left
off, as in `{a:42, b:17}`. Variable references as key
expressions use the value of the variable as the key. Key
expressions other than constant literals, identifiers, or
variable references, need to be parenthesized, e.g.,
`{("a"+"b"):59}`.
The value can be any expression (although you may need to wrap
it in parentheses if, for example, it contains colons), which
gets applied to the {} expression's input (remember, all
filters have an input and an output).
{foo: .bar}
will produce the JSON object `{"foo": 42}` if given the JSON
object `{"bar":42, "baz":43}` as its input. You can use this
to select particular fields of an object: if the input is an
object with "user", "title", "id", and "content" fields and
you just want "user" and "title", you can write
{user: .user, title: .title}
Because that is so common, there's a shortcut syntax for it:
`{user, title}`.
If one of the expressions produces multiple results,
multiple dictionaries will be produced. If the input's
{"user":"stedolan","titles":["JQ Primer", "More JQ"]}
then the expression
{user, title: .titles[]}
will produce two outputs:
{"user":"stedolan", "title": "JQ Primer"}
{"user":"stedolan", "title": "More JQ"}
Putting parentheses around the key means it will be evaluated as an
expression. With the same input as above,
{(.user): .titles}
produces
{"stedolan": ["JQ Primer", "More JQ"]}
Variable references as keys use the value of the variable as
the key. Without a value then the variable's name becomes the
key and its value becomes the value,
"f o o" as $foo | "b a r" as $bar | {$foo, $bar:$foo}
produces
{"foo":"f o o","b a r":"f o o"}
Example: {user, title: .titles[]}
Input: {"user":"stedolan","titles":["JQ Primer", "More JQ"]}
Output: {"user":"stedolan", "title": "JQ Primer"}
{"user":"stedolan", "title": "More JQ"}
Example: {(.user): .titles}
Input: {"user":"stedolan","titles":["JQ Primer", "More JQ"]}
Output: {"stedolan": ["JQ Primer", "More JQ"]}
----------------------------------------------------------------------------
Recursive Descent: `..`
----------------------------------------------------------------------------
Recursively descends `.`, producing every value. This is the
same as the zero-argument `recurse` builtin (see below). This
is intended to resemble the XPath `//` operator. Note that
`..a` does not work; use `.. | .a` instead. In the example
below we use `.. | .a?` to find all the values of object keys
"a" in any object found "below" `.`.
This is particularly useful in conjunction with `path(EXP)`
(also see below) and the `?` operator.
Example: .. | .a?
Input: [[{"a":1}]]
Output: 1
============================================================================
SECTION: Builtin operators and functions
============================================================================
Some jq operators (for instance, `+`) do different things
depending on the type of their arguments (arrays, numbers,
etc.). However, jq never does implicit type conversions. If you
try to add a string to an object you'll get an error message and
no result.
Please note that all numbers are converted to IEEE754 double precision
floating point representation. Arithmetic and logical operators are working
with these converted doubles. Results of all such operations are also limited
to the double precision.
The only exception to this behaviour of number is a snapshot of original number
literal. When a number which originally was provided as a literal is never
mutated until the end of the program then it is printed to the output in its
original literal form. This also includes cases when the original literal
would be truncated when converted to the IEEE754 double precision floating point
number.
----------------------------------------------------------------------------
Addition: `+`
----------------------------------------------------------------------------
The operator `+` takes two filters, applies them both
to the same input, and adds the results together. What
"adding" means depends on the types involved:
- **Numbers** are added by normal arithmetic.
- **Arrays** are added by being concatenated into a larger array.
- **Strings** are added by being joined into a larger string.
- **Objects** are added by merging, that is, inserting all
the key-value pairs from both objects into a single
combined object. If both objects contain a value for the
same key, the object on the right of the `+` wins. (For
recursive merge use the `*` operator.)
`null` can be added to any value, and returns the other
value unchanged.
Example: .a + 1
Input: {"a": 7}
Output: 8
Example: .a + .b
Input: {"a": [1,2], "b": [3,4]}
Output: [1,2,3,4]
Example: .a + null
Input: {"a": 1}
Output: 1
Example: .a + 1
Input: {}
Output: 1
Example: {a: 1} + {b: 2} + {c: 3} + {a: 42}
Input: null
Output: {"a": 42, "b": 2, "c": 3}
----------------------------------------------------------------------------
Subtraction: `-`
----------------------------------------------------------------------------
As well as normal arithmetic subtraction on numbers, the `-`
operator can be used on arrays to remove all occurrences of
the second array's elements from the first array.
Example: 4 - .a
Input: {"a":3}
Output: 1
Example: . - ["xml", "yaml"]
Input: ["xml", "yaml", "json"]
Output: ["json"]
----------------------------------------------------------------------------
Multiplication, division, modulo: `*`, `/`, `%`
----------------------------------------------------------------------------
These infix operators behave as expected when given two numbers.
Division by zero raises an error. `x % y` computes x modulo y.
Multiplying a string by a number produces the concatenation of
that string that many times. `"x" * 0` produces `""`.
Dividing a string by another splits the first using the second
as separators.
Multiplying two objects will merge them recursively: this works
like addition but if both objects contain a value for the
same key, and the values are objects, the two are merged with
the same strategy.
Example: 10 / . * 3
Input: 5
Output: 6
Example: . / ", "
Input: "a, b,c,d, e"
Output: ["a","b,c,d","e"]
Example: {"k": {"a": 1, "b": 2}} * {"k": {"a": 0,"c": 3}}
Input: null
Output: {"k": {"a": 0, "b": 2, "c": 3}}
Example: .[] | (1 / .)?
Input: [1,0,-1]
Output: 1
-1
----------------------------------------------------------------------------
`abs`
----------------------------------------------------------------------------
The builtin function `abs` is defined naively as: `if . < 0 then - . else . end`.
For numeric input, this is the absolute value. See the
section on the identity filter for the implications of this
definition for numeric input.
To compute the absolute value of a number as a floating point number, you may wish use `fabs`.
Example: map(abs)
Input: [-10, -1.1, -1e-1]
Output: [10,1.1,1e-1]
----------------------------------------------------------------------------
`length`
----------------------------------------------------------------------------
The builtin function `length` gets the length of various
different types of value:
- The length of a **string** is the number of Unicode
codepoints it contains (which will be the same as its
JSON-encoded length in bytes if it's pure ASCII).
- The length of a **number** is its absolute value.
- The length of an **array** is the number of elements.
- The length of an **object** is the number of key-value pairs.
- The length of **null** is zero.
- It is an error to use `length` on a **boolean**.
Example: .[] | length
Input: [[1,2], "string", {"a":2}, null, -5]
Output: 2
6
1
0
5
----------------------------------------------------------------------------
`utf8bytelength`
----------------------------------------------------------------------------
The builtin function `utf8bytelength` outputs the number of
bytes used to encode a string in UTF-8.
Example: utf8bytelength
Input: "\u03bc"
Output: 2
----------------------------------------------------------------------------
`keys`, `keys_unsorted`
----------------------------------------------------------------------------
The builtin function `keys`, when given an object, returns
its keys in an array.
The keys are sorted "alphabetically", by unicode codepoint
order. This is not an order that makes particular sense in
any particular language, but you can count on it being the
same for any two objects with the same set of keys,
regardless of locale settings.
When `keys` is given an array, it returns the valid indices
for that array: the integers from 0 to length-1.
The `keys_unsorted` function is just like `keys`, but if
the input is an object then the keys will not be sorted,
instead the keys will roughly be in insertion order.
Example: keys
Input: {"abc": 1, "abcd": 2, "Foo": 3}
Output: ["Foo", "abc", "abcd"]
Example: keys
Input: [42,3,35]
Output: [0,1,2]
----------------------------------------------------------------------------
`has(key)`
----------------------------------------------------------------------------
The builtin function `has` returns whether the input object
has the given key, or the input array has an element at the
given index.
`has($key)` has the same effect as checking whether `$key`
is a member of the array returned by `keys`, although `has`
will be faster.
Example: map(has("foo"))
Input: [{"foo": 42}, {}]
Output: [true, false]
Example: map(has(2))
Input: [[0,1], ["a","b","c"]]
Output: [false, true]
----------------------------------------------------------------------------
`in`
----------------------------------------------------------------------------
The builtin function `in` returns whether or not the input key is in the
given object, or the input index corresponds to an element
in the given array. It is, essentially, an inversed version
of `has`.
Example: .[] | in({"foo": 42})
Input: ["foo", "bar"]
Output: true
false
Example: map(in([0,1]))
Input: [2, 0]
Output: [false, true]
----------------------------------------------------------------------------
`map(f)`, `map_values(f)`
----------------------------------------------------------------------------
For any filter `f`, `map(f)` and `map_values(f)` apply `f`
to each of the values in the input array or object, that is,
to the values of `.[]`.
In the absence of errors, `map(f)` always outputs an array
whereas `map_values(f)` outputs an array if given an array,
or an object if given an object.
When the input to `map_values(f)` is an object, the output
object has the same keys as the input object except for
those keys whose values when piped to `f` produce no values
at all.
The key difference between `map(f)` and `map_values(f)` is
that the former simply forms an array from all the values of
`($x|f)` for each value, `$x`, in the input array or object,
but `map_values(f)` only uses `first($x|f)`.
Specifically, for object inputs, `map_values(f)` constructs
the output object by examining in turn the value of
`first(.[$k]|f)` for each key, `$k`, of the input. If this
expression produces no values, then the corresponding key
will be dropped; otherwise, the output object will have that
value at the key, `$k`.
Here are some examples to clarify the behavior of `map` and
`map_values` when applied to arrays. These examples assume the
input is `[1]` in all cases:
map(.+1) #=> [2]
map(., .) #=> [1,1]
map(empty) #=> []
map_values(.+1) #=> [2]
map_values(., .) #=> [1]
map_values(empty) #=> []
`map(f)` is equivalent to `[.[] | f]` and
`map_values(f)` is equivalent to `.[] |= f`.
In fact, these are their implementations.
Example: map(.+1)
Input: [1,2,3]
Output: [2,3,4]
Example: map_values(.+1)
Input: {"a": 1, "b": 2, "c": 3}
Output: {"a": 2, "b": 3, "c": 4}
Example: map(., .)
Input: [1,2]
Output: [1,1,2,2]
Example: map_values(. // empty)
Input: {"a": null, "b": true, "c": false}
Output: {"b":true}
----------------------------------------------------------------------------
`pick(pathexps)`
----------------------------------------------------------------------------
Emit the projection of the input object or array defined by the
specified sequence of path expressions, such that if `p` is any
one of these specifications, then `(. | p)` will evaluate to the
same value as `(. | pick(pathexps) | p)`. For arrays, negative
indices and `.[m:n]` specifications should not be used.
Example: pick(.a, .b.c, .x)
Input: {"a": 1, "b": {"c": 2, "d": 3}, "e": 4}
Output: {"a":1,"b":{"c":2},"x":null}
Example: pick(.[2], .[0], .[0])
Input: [1,2,3,4]
Output: [1,null,3]
----------------------------------------------------------------------------
`path(path_expression)`
----------------------------------------------------------------------------
Outputs array representations of the given path expression
in `.`. The outputs are arrays of strings (object keys)
and/or numbers (array indices).
Path expressions are jq expressions like `.a`, but also `.[]`.
There are two types of path expressions: ones that can match
exactly, and ones that cannot. For example, `.a.b.c` is an
exact match path expression, while `.a[].b` is not.
`path(exact_path_expression)` will produce the array
representation of the path expression even if it does not
exist in `.`, if `.` is `null` or an array or an object.
`path(pattern)` will produce array representations of the
paths matching `pattern` if the paths exist in `.`.
Note that the path expressions are not different from normal
expressions. The expression
`path(..|select(type=="boolean"))` outputs all the paths to
boolean values in `.`, and only those paths.
Example: path(.a[0].b)
Input: null
Output: ["a",0,"b"]
Example: [path(..)]
Input: {"a":[{"b":1}]}
Output: [[],["a"],["a",0],["a",0,"b"]]
----------------------------------------------------------------------------
`del(path_expression)`
----------------------------------------------------------------------------
The builtin function `del` removes a key and its corresponding
value from an object.
Example: del(.foo)
Input: {"foo": 42, "bar": 9001, "baz": 42}
Output: {"bar": 9001, "baz": 42}
Example: del(.[1, 2])
Input: ["foo", "bar", "baz"]
Output: ["foo"]
----------------------------------------------------------------------------
`getpath(PATHS)`
----------------------------------------------------------------------------
The builtin function `getpath` outputs the values in `.` found
at each path in `PATHS`.
Example: getpath(["a","b"])
Input: null
Output: null
Example: [getpath(["a","b"], ["a","c"])]
Input: {"a":{"b":0, "c":1}}
Output: [0, 1]
----------------------------------------------------------------------------
`setpath(PATHS; VALUE)`
----------------------------------------------------------------------------
The builtin function `setpath` sets the `PATHS` in `.` to `VALUE`.
Example: setpath(["a","b"]; 1)
Input: null
Output: {"a": {"b": 1}}
Example: setpath(["a","b"]; 1)
Input: {"a":{"b":0}}
Output: {"a": {"b": 1}}
Example: setpath([0,"a"]; 1)
Input: null
Output: [{"a":1}]
----------------------------------------------------------------------------
`delpaths(PATHS)`
----------------------------------------------------------------------------
The builtin function `delpaths` deletes the `PATHS` in `.`.
`PATHS` must be an array of paths, where each path is an array
of strings and numbers.
Example: delpaths([["a","b"]])
Input: {"a":{"b":1},"x":{"y":2}}
Output: {"a":{},"x":{"y":2}}
----------------------------------------------------------------------------
`to_entries`, `from_entries`, `with_entries(f)`
----------------------------------------------------------------------------
These functions convert between an object and an array of
key-value pairs. If `to_entries` is passed an object, then
for each `k: v` entry in the input, the output array
includes `{"key": k, "value": v}`.
`from_entries` does the opposite conversion, and `with_entries(f)`
is a shorthand for `to_entries | map(f) | from_entries`, useful for
doing some operation to all keys and values of an object.
`from_entries` accepts `"key"`, `"Key"`, `"name"`, `"Name"`,
`"value"`, and `"Value"` as keys.
Example: to_entries
Input: {"a": 1, "b": 2}
Output: [{"key":"a", "value":1}, {"key":"b", "value":2}]
Example: from_entries
Input: [{"key":"a", "value":1}, {"key":"b", "value":2}]
Output: {"a": 1, "b": 2}
Example: with_entries(.key |= "KEY_" + .)
Input: {"a": 1, "b": 2}
Output: {"KEY_a": 1, "KEY_b": 2}
----------------------------------------------------------------------------
`select(boolean_expression)`
----------------------------------------------------------------------------
The function `select(f)` produces its input unchanged if
`f` returns true for that input, and produces no output
otherwise.
It's useful for filtering lists: `[1,2,3] | map(select(. >= 2))`
will give you `[2,3]`.
Example: map(select(. >= 2))
Input: [1,5,3,0,7]
Output: [5,3,7]
Example: .[] | select(.id == "second")
Input: [{"id": "first", "val": 1}, {"id": "second", "val": 2}]
Output: {"id": "second", "val": 2}
----------------------------------------------------------------------------
`arrays`, `objects`, `iterables`, `booleans`, `numbers`, `normals`, `finites`, `strings`, `nulls`, `values`, `scalars`
----------------------------------------------------------------------------
These built-ins select only inputs that are arrays, objects,
iterables (arrays or objects), booleans, numbers, normal
numbers, finite numbers, strings, null, non-null values, and
non-iterables, respectively.
Example: .[]|numbers
Input: [[],{},1,"foo",null,true,false]
Output: 1
----------------------------------------------------------------------------
`empty`
----------------------------------------------------------------------------
`empty` returns no results. None at all. Not even `null`.
It's useful on occasion. You'll know if you need it :)
Example: 1, empty, 2
Input: null
Output: 1
2
Example: [1,2,empty,3]
Input: null
Output: [1,2,3]
----------------------------------------------------------------------------
`error`, `error(message)`
----------------------------------------------------------------------------
Produces an error with the input value, or with the message
given as the argument. Errors can be caught with try/catch;
see below.
Example: try error catch .
Input: "error message"
Output: "error message"
Example: try error("invalid value: \(.)") catch .
Input: 42
Output: "invalid value: 42"
----------------------------------------------------------------------------
`halt`
----------------------------------------------------------------------------
Stops the jq program with no further outputs. jq will exit
with exit status `0`.
----------------------------------------------------------------------------
`halt_error`, `halt_error(exit_code)`
----------------------------------------------------------------------------
Stops the jq program with no further outputs. The input will
be printed on `stderr` as raw output (i.e., strings will not
have double quotes) with no decoration, not even a newline.
The given `exit_code` (defaulting to `5`) will be jq's exit
status.
For example, `"Error: something went wrong\n"|halt_error(1)`.
----------------------------------------------------------------------------
`$__loc__`
----------------------------------------------------------------------------
Produces an object with a "file" key and a "line" key, with
the filename and line number where `$__loc__` occurs, as
values.
Example: try error("\($__loc__)") catch .
Input: null
Output: "{\"file\":\"<top-level>\",\"line\":1}"
----------------------------------------------------------------------------
`paths`, `paths(node_filter)`
----------------------------------------------------------------------------
`paths` outputs the paths to all the elements in its input
(except it does not output the empty list, representing .
itself).
`paths(f)` outputs the paths to any values for which `f` is `true`.
That is, `paths(type == "number")` outputs the paths to all numeric
values.
Example: [paths]
Input: [1,[[],{"a":2}]]
Output: [[0],[1],[1,0],[1,1],[1,1,"a"]]
Example: [paths(type == "number")]
Input: [1,[[],{"a":2}]]
Output: [[0],[1,1,"a"]]
----------------------------------------------------------------------------
`add`, `add(generator)`
----------------------------------------------------------------------------
The filter `add` takes as input an array, and produces as
output the elements of the array added together. This might
mean summed, concatenated or merged depending on the types
of the elements of the input array - the rules are the same
as those for the `+` operator (described above).
If the input is an empty array, `add` returns `null`.
`add(generator)` operates on the given generator rather than
the input.
Example: add
Input: ["a","b","c"]
Output: "abc"
Example: add
Input: [1, 2, 3]
Output: 6
Example: add
Input: []
Output: null
Example: add(.[].a)
Input: [{"a":3}, {"a":5}, {"b":6}]
Output: 8
----------------------------------------------------------------------------
`any`, `any(condition)`, `any(generator; condition)`
----------------------------------------------------------------------------
The filter `any` takes as input an array of boolean values,
and produces `true` as output if any of the elements of
the array are `true`.
If the input is an empty array, `any` returns `false`.
The `any(condition)` form applies the given condition to the
elements of the input array.
The `any(generator; condition)` form applies the given
condition to all the outputs of the given generator.
Example: any
Input: [true, false]
Output: true
Example: any
Input: [false, false]
Output: false
Example: any
Input: []
Output: false
----------------------------------------------------------------------------
`all`, `all(condition)`, `all(generator; condition)`
----------------------------------------------------------------------------
The filter `all` takes as input an array of boolean values,
and produces `true` as output if all of the elements of
the array are `true`.
The `all(condition)` form applies the given condition to the
elements of the input array.
The `all(generator; condition)` form applies the given
condition to all the outputs of the given generator.
If the input is an empty array, `all` returns `true`.
Example: all
Input: [true, false]
Output: false
Example: all
Input: [true, true]
Output: true
Example: all
Input: []
Output: true
----------------------------------------------------------------------------
`flatten`, `flatten(depth)`
----------------------------------------------------------------------------
The filter `flatten` takes as input an array of nested arrays,
and produces a flat array in which all arrays inside the original
array have been recursively replaced by their values. You can pass
an argument to it to specify how many levels of nesting to flatten.
`flatten(2)` is like `flatten`, but going only up to two
levels deep.
Example: flatten
Input: [1, [2], [[3]]]
Output: [1, 2, 3]
Example: flatten(1)
Input: [1, [2], [[3]]]
Output: [1, 2, [3]]
Example: flatten
Input: [[]]
Output: []
Example: flatten
Input: [{"foo": "bar"}, [{"foo": "baz"}]]
Output: [{"foo": "bar"}, {"foo": "baz"}]
----------------------------------------------------------------------------
`range(upto)`, `range(from; upto)`, `range(from; upto; by)`
----------------------------------------------------------------------------
The `range` function produces a range of numbers. `range(4; 10)`
produces 6 numbers, from 4 (inclusive) to 10 (exclusive). The numbers
are produced as separate outputs. Use `[range(4; 10)]` to get a range as
an array.
The one argument form generates numbers from 0 to the given
number, with an increment of 1.
The two argument form generates numbers from `from` to `upto`
with an increment of 1.
The three argument form generates numbers `from` to `upto`
with an increment of `by`.
Example: range(2; 4)
Input: null
Output: 2
3
Example: [range(2; 4)]
Input: null
Output: [2,3]
Example: [range(4)]
Input: null
Output: [0,1,2,3]
Example: [range(0; 10; 3)]
Input: null
Output: [0,3,6,9]
Example: [range(0; 10; -1)]
Input: null
Output: []
Example: [range(0; -5; -1)]
Input: null
Output: [0,-1,-2,-3,-4]
----------------------------------------------------------------------------
`floor`
----------------------------------------------------------------------------
The `floor` function returns the floor of its numeric input.
Example: floor
Input: 3.14159
Output: 3
----------------------------------------------------------------------------
`sqrt`
----------------------------------------------------------------------------
The `sqrt` function returns the square root of its numeric input.
Example: sqrt
Input: 9
Output: 3
----------------------------------------------------------------------------
`tonumber`
----------------------------------------------------------------------------
The `tonumber` function parses its input as a number. It
will convert correctly-formatted strings to their numeric
equivalent, leave numbers alone, and give an error on all other input.
Example: .[] | tonumber
Input: [1, "1"]
Output: 1
1
----------------------------------------------------------------------------
`toboolean`
----------------------------------------------------------------------------
The `toboolean` function parses its input as a boolean. It
will convert correctly-formatted strings to their boolean
equivalent, leave booleans alone, and give an error on all other input.
Example: .[] | toboolean
Input: ["true", "false", true, false]
Output: true
false
true
false
----------------------------------------------------------------------------
`tostring`
----------------------------------------------------------------------------
The `tostring` function prints its input as a
string. Strings are left unchanged, and all other values are
JSON-encoded.
Example: .[] | tostring
Input: [1, "1", [1]]
Output: "1"
"1"
"[1]"
----------------------------------------------------------------------------
`type`
----------------------------------------------------------------------------
The `type` function returns the type of its argument as a
string, which is one of null, boolean, number, string, array
or object.
Example: map(type)
Input: [0, false, [], {}, null, "hello"]
Output: ["number", "boolean", "array", "object", "null", "string"]
----------------------------------------------------------------------------
`infinite`, `nan`, `isinfinite`, `isnan`, `isfinite`, `isnormal`
----------------------------------------------------------------------------
Some arithmetic operations can yield infinities and "not a
number" (NaN) values. The `isinfinite` builtin returns `true`
if its input is infinite. The `isnan` builtin returns `true`
if its input is a NaN. The `infinite` builtin returns a
positive infinite value. The `nan` builtin returns a NaN.
The `isnormal` builtin returns true if its input is a normal
number.
Note that division by zero raises an error.
Currently most arithmetic operations operating on infinities,
NaNs, and sub-normals do not raise errors.
Example: .[] | (infinite * .) < 0
Input: [-1, 1]
Output: true
false
Example: infinite, nan | type
Input: null
Output: "number"
"number"
----------------------------------------------------------------------------
`sort`, `sort_by(path_expression)`
----------------------------------------------------------------------------
The `sort` functions sorts its input, which must be an
array. Values are sorted in the following order:
* `null`
* `false`
* `true`
* numbers
* strings, in alphabetical order (by unicode codepoint value)
* arrays, in lexical order
* objects
The ordering for objects is a little complex: first they're
compared by comparing their sets of keys (as arrays in
sorted order), and if their keys are equal then the values
are compared key by key.
`sort_by` may be used to sort by a particular field of an
object, or by applying any jq filter. `sort_by(f)` compares
two elements by comparing the result of `f` on each element.
When `f` produces multiple values, it firstly compares the
first values, and the second values if the first values are
equal, and so on.
Example: sort
Input: [8,3,null,6]
Output: [null,3,6,8]
Example: sort_by(.foo)
Input: [{"foo":4, "bar":10}, {"foo":3, "bar":10}, {"foo":2, "bar":1}]
Output: [{"foo":2, "bar":1}, {"foo":3, "bar":10}, {"foo":4, "bar":10}]
Example: sort_by(.foo, .bar)
Input: [{"foo":4, "bar":10}, {"foo":3, "bar":20}, {"foo":2, "bar":1}, {"foo":3, "bar":10}]
Output: [{"foo":2, "bar":1}, {"foo":3, "bar":10}, {"foo":3, "bar":20}, {"foo":4, "bar":10}]
----------------------------------------------------------------------------
`group_by(path_expression)`
----------------------------------------------------------------------------
`group_by(.foo)` takes as input an array, groups the
elements having the same `.foo` field into separate arrays,
and produces all of these arrays as elements of a larger
array, sorted by the value of the `.foo` field.
Any jq expression, not just a field access, may be used in
place of `.foo`. The sorting order is the same as described
in the `sort` function above.
Example: group_by(.foo)
Input: [{"foo":1, "bar":10}, {"foo":3, "bar":100}, {"foo":1, "bar":1}]
Output: [[{"foo":1, "bar":10}, {"foo":1, "bar":1}], [{"foo":3, "bar":100}]]
----------------------------------------------------------------------------
`min`, `max`, `min_by(path_exp)`, `max_by(path_exp)`
----------------------------------------------------------------------------
Find the minimum or maximum element of the input array.
The `min_by(path_exp)` and `max_by(path_exp)` functions allow
you to specify a particular field or property to examine, e.g.
`min_by(.foo)` finds the object with the smallest `foo` field.
Example: min
Input: [5,4,2,7]
Output: 2
Example: max_by(.foo)
Input: [{"foo":1, "bar":14}, {"foo":2, "bar":3}]
Output: {"foo":2, "bar":3}
----------------------------------------------------------------------------
`unique`, `unique_by(path_exp)`
----------------------------------------------------------------------------
The `unique` function takes as input an array and produces
an array of the same elements, in sorted order, with
duplicates removed.
The `unique_by(path_exp)` function will keep only one element
for each value obtained by applying the argument. Think of it
as making an array by taking one element out of every group
produced by `group`.
Example: unique
Input: [1,2,5,3,5,3,1,3]
Output: [1,2,3,5]
Example: unique_by(.foo)
Input: [{"foo": 1, "bar": 2}, {"foo": 1, "bar": 3}, {"foo": 4, "bar": 5}]
Output: [{"foo": 1, "bar": 2}, {"foo": 4, "bar": 5}]
Example: unique_by(length)
Input: ["chunky", "bacon", "kitten", "cicada", "asparagus"]
Output: ["bacon", "chunky", "asparagus"]
----------------------------------------------------------------------------
`reverse`
----------------------------------------------------------------------------
This function reverses an array.
Example: reverse
Input: [1,2,3,4]
Output: [4,3,2,1]
----------------------------------------------------------------------------
`contains(element)`
----------------------------------------------------------------------------
The filter `contains(b)` will produce true if b is
completely contained within the input. A string B is
contained in a string A if B is a substring of A. An array B
is contained in an array A if all elements in B are
contained in any element in A. An object B is contained in
object A if all of the values in B are contained in the
value in A with the same key. All other types are assumed to
be contained in each other if they are equal.
Example: contains("bar")
Input: "foobar"
Output: true
Example: contains(["baz", "bar"])
Input: ["foobar", "foobaz", "blarp"]
Output: true
Example: contains(["bazzzzz", "bar"])
Input: ["foobar", "foobaz", "blarp"]
Output: false
Example: contains({foo: 12, bar: [{barp: 12}]})
Input: {"foo": 12, "bar":[1,2,{"barp":12, "blip":13}]}
Output: true
Example: contains({foo: 12, bar: [{barp: 15}]})
Input: {"foo": 12, "bar":[1,2,{"barp":12, "blip":13}]}
Output: false
----------------------------------------------------------------------------
`indices(s)`
----------------------------------------------------------------------------
Outputs an array containing the indices in `.` where `s`
occurs. The input may be an array, in which case if `s` is an
array then the indices output will be those where all elements
in `.` match those of `s`.
Example: indices(", ")
Input: "a,b, cd, efg, hijk"
Output: [3,7,12]
Example: indices(1)
Input: [0,1,2,1,3,1,4]
Output: [1,3,5]
Example: indices([1,2])
Input: [0,1,2,3,1,4,2,5,1,2,6,7]
Output: [1,8]
----------------------------------------------------------------------------
`index(s)`, `rindex(s)`
----------------------------------------------------------------------------
Outputs the index of the first (`index`) or last (`rindex`)
occurrence of `s` in the input.
Example: index(", ")
Input: "a,b, cd, efg, hijk"
Output: 3
Example: index(1)
Input: [0,1,2,1,3,1,4]
Output: 1
Example: index([1,2])
Input: [0,1,2,3,1,4,2,5,1,2,6,7]
Output: 1
Example: rindex(", ")
Input: "a,b, cd, efg, hijk"
Output: 12
Example: rindex(1)
Input: [0,1,2,1,3,1,4]
Output: 5
Example: rindex([1,2])
Input: [0,1,2,3,1,4,2,5,1,2,6,7]
Output: 8
----------------------------------------------------------------------------
`inside`
----------------------------------------------------------------------------
The filter `inside(b)` will produce true if the input is
completely contained within b. It is, essentially, an
inversed version of `contains`.
Example: inside("foobar")
Input: "bar"
Output: true
Example: inside(["foobar", "foobaz", "blarp"])
Input: ["baz", "bar"]
Output: true
Example: inside(["foobar", "foobaz", "blarp"])
Input: ["bazzzzz", "bar"]
Output: false
Example: inside({"foo": 12, "bar":[1,2,{"barp":12, "blip":13}]})
Input: {"foo": 12, "bar": [{"barp": 12}]}
Output: true
Example: inside({"foo": 12, "bar":[1,2,{"barp":12, "blip":13}]})
Input: {"foo": 12, "bar": [{"barp": 15}]}
Output: false
----------------------------------------------------------------------------
`startswith(str)`
----------------------------------------------------------------------------
Outputs `true` if . starts with the given string argument.
Example: [.[]|startswith("foo")]
Input: ["fo", "foo", "barfoo", "foobar", "barfoob"]
Output: [false, true, false, true, false]
----------------------------------------------------------------------------
`endswith(str)`
----------------------------------------------------------------------------
Outputs `true` if . ends with the given string argument.
Example: [.[]|endswith("foo")]
Input: ["foobar", "barfoo"]
Output: [false, true]
----------------------------------------------------------------------------
`combinations`, `combinations(n)`
----------------------------------------------------------------------------
Outputs all combinations of the elements of the arrays in the
input array. If given an argument `n`, it outputs all combinations
of `n` repetitions of the input array.
Example: combinations
Input: [[1,2], [3, 4]]
Output: [1, 3]
[1, 4]
[2, 3]
[2, 4]
Example: combinations(2)
Input: [0, 1]
Output: [0, 0]
[0, 1]
[1, 0]
[1, 1]
----------------------------------------------------------------------------
`ltrimstr(str)`
----------------------------------------------------------------------------
Outputs its input with the given prefix string removed, if it
starts with it.
Example: [.[]|ltrimstr("foo")]
Input: ["fo", "foo", "barfoo", "foobar", "afoo"]
Output: ["fo","","barfoo","bar","afoo"]
----------------------------------------------------------------------------
`rtrimstr(str)`
----------------------------------------------------------------------------
Outputs its input with the given suffix string removed, if it
ends with it.
Example: [.[]|rtrimstr("foo")]
Input: ["fo", "foo", "barfoo", "foobar", "foob"]
Output: ["fo","","bar","foobar","foob"]
----------------------------------------------------------------------------
`trimstr(str)`
----------------------------------------------------------------------------
Outputs its input with the given string removed at both ends, if it
starts or ends with it.
Example: [.[]|trimstr("foo")]
Input: ["fo", "foo", "barfoo", "foobarfoo", "foob"]
Output: ["fo","","bar","bar","b"]
----------------------------------------------------------------------------
`trim`, `ltrim`, `rtrim`
----------------------------------------------------------------------------
`trim` trims both leading and trailing whitespace.
`ltrim` trims only leading (left side) whitespace.
`rtrim` trims only trailing (right side) whitespace.
Whitespace characters are the usual `" "`, `"\n"` `"\t"`, `"\r"`
and also all characters in the Unicode character database with the
whitespace property. Note that what considers whitespace might
change in the future.
Example: trim, ltrim, rtrim
Input: " abc "
Output: "abc"
"abc "
" abc"
----------------------------------------------------------------------------
`explode`
----------------------------------------------------------------------------
Converts an input string into an array of the string's
codepoint numbers.
Example: explode
Input: "foobar"
Output: [102,111,111,98,97,114]
----------------------------------------------------------------------------
`implode`
----------------------------------------------------------------------------
The inverse of explode.
Example: implode
Input: [65, 66, 67]
Output: "ABC"
----------------------------------------------------------------------------
`split(str)`
----------------------------------------------------------------------------
Splits an input string on the separator argument.
`split` can also split on regex matches when called with
two arguments (see the regular expressions section below).
Example: split(", ")
Input: "a, b,c,d, e, "
Output: ["a","b,c,d","e",""]
----------------------------------------------------------------------------
`join(str)`
----------------------------------------------------------------------------
Joins the array of elements given as input, using the
argument as separator. It is the inverse of `split`: that is,
running `split("foo") | join("foo")` over any input string
returns said input string.
Numbers and booleans in the input are converted to strings.
Null values are treated as empty strings. Arrays and objects
in the input are not supported.
Example: join(", ")
Input: ["a","b,c,d","e"]
Output: "a, b,c,d, e"
Example: join(" ")
Input: ["a",1,2.3,true,null,false]
Output: "a 1 2.3 true false"
----------------------------------------------------------------------------
`ascii_downcase`, `ascii_upcase`
----------------------------------------------------------------------------
Emit a copy of the input string with its alphabetic characters (a-z and A-Z)
converted to the specified case.
Example: ascii_upcase
Input: "useful but not for é"
Output: "USEFUL BUT NOT FOR é"
----------------------------------------------------------------------------
`while(cond; update)`
----------------------------------------------------------------------------
The `while(cond; update)` function allows you to repeatedly
apply an update to `.` until `cond` is false.
Note that `while(cond; update)` is internally defined as a
recursive jq function. Recursive calls within `while` will
not consume additional memory if `update` produces at most one
output for each input. See advanced topics below.
Example: [while(.<100; .*2)]
Input: 1
Output: [1,2,4,8,16,32,64]
----------------------------------------------------------------------------
`repeat(exp)`
----------------------------------------------------------------------------
The `repeat(exp)` function allows you to repeatedly
apply expression `exp` to `.` until an error is raised.
Note that `repeat(exp)` is internally defined as a
recursive jq function. Recursive calls within `repeat` will
not consume additional memory if `exp` produces at most one
output for each input. See advanced topics below.
Example: [repeat(.*2, error)?]
Input: 1
Output: [2]
----------------------------------------------------------------------------
`until(cond; next)`
----------------------------------------------------------------------------
The `until(cond; next)` function allows you to repeatedly
apply the expression `next`, initially to `.` then to its own
output, until `cond` is true. For example, this can be used
to implement a factorial function (see below).
Note that `until(cond; next)` is internally defined as a
recursive jq function. Recursive calls within `until()` will
not consume additional memory if `next` produces at most one
output for each input. See advanced topics below.
Example: [.,1]|until(.[0] < 1; [.[0] - 1, .[1] * .[0]])|.[1]
Input: 4
Output: 24
----------------------------------------------------------------------------
`recurse(f)`, `recurse`, `recurse(f; condition)`
----------------------------------------------------------------------------
The `recurse(f)` function allows you to search through a
recursive structure, and extract interesting data from all
levels. Suppose your input represents a filesystem:
{"name": "/", "children": [
{"name": "/bin", "children": [
{"name": "/bin/ls", "children": []},
{"name": "/bin/sh", "children": []}]},
{"name": "/home", "children": [
{"name": "/home/stephen", "children": [
{"name": "/home/stephen/jq", "children": []}]}]}]}
Now suppose you want to extract all of the filenames
present. You need to retrieve `.name`, `.children[].name`,
`.children[].children[].name`, and so on. You can do this
with:
recurse(.children[]) | .name
When called without an argument, `recurse` is equivalent to
`recurse(.[]?)`.
`recurse(f)` is identical to `recurse(f; true)` and can be
used without concerns about recursion depth.
`recurse(f; condition)` is a generator which begins by
emitting . and then emits in turn .|f, .|f|f, .|f|f|f, ... so long
as the computed value satisfies the condition. For example,
to generate all the integers, at least in principle, one
could write `recurse(.+1; true)`.
The recursive calls in `recurse` will not consume additional
memory whenever `f` produces at most a single output for each
input.
Example: recurse(.foo[])
Input: {"foo":[{"foo": []}, {"foo":[{"foo":[]}]}]}
Output: {"foo":[{"foo":[]},{"foo":[{"foo":[]}]}]}
{"foo":[]}
{"foo":[{"foo":[]}]}
{"foo":[]}
Example: recurse
Input: {"a":0,"b":[1]}
Output: {"a":0,"b":[1]}
0
[1]
1
Example: recurse(. * .; . < 20)
Input: 2
Output: 2
4
16
----------------------------------------------------------------------------
`walk(f)`
----------------------------------------------------------------------------
The `walk(f)` function applies f recursively to every
component of the input entity. When an array is
encountered, f is first applied to its elements and then to
the array itself; when an object is encountered, f is first
applied to all the values and then to the object. In
practice, f will usually test the type of its input, as
illustrated in the following examples. The first example
highlights the usefulness of processing the elements of an
array of arrays before processing the array itself. The second
example shows how all the keys of all the objects within the
input can be considered for alteration.
Example: walk(if type == "array" then sort else . end)
Input: [[4, 1, 7], [8, 5, 2], [3, 6, 9]]
Output: [[1,4,7],[2,5,8],[3,6,9]]
Example: walk( if type == "object" then with_entries( .key |= sub( "^_+"; "") ) else . end )
Input: [ { "_a": { "__b": 2 } } ]
Output: [{"a":{"b":2}}]
----------------------------------------------------------------------------
`have_literal_numbers`
----------------------------------------------------------------------------
This builtin returns true if jq's build configuration
includes support for preservation of input number literals.
----------------------------------------------------------------------------
`have_decnum`
----------------------------------------------------------------------------
This builtin returns true if jq was built with "decnum",
which is the current literal number preserving numeric
backend implementation for jq.
----------------------------------------------------------------------------
`$JQ_BUILD_CONFIGURATION`
----------------------------------------------------------------------------
This builtin binding shows the jq executable's build
configuration. Its value has no particular format, but
it can be expected to be at least the `./configure`
command-line arguments, and may be enriched in the
future to include the version strings for the build
tooling used.
Note that this can be overridden in the command-line
with `--arg` and related options.
----------------------------------------------------------------------------
`$ENV`, `env`
----------------------------------------------------------------------------
`$ENV` is an object representing the environment variables as
set when the jq program started.
`env` outputs an object representing jq's current environment.
At the moment there is no builtin for setting environment
variables.
Example: $ENV.PAGER
Input: null
Output: "less"
Example: env.PAGER
Input: null
Output: "less"
----------------------------------------------------------------------------
`transpose`
----------------------------------------------------------------------------
Transpose a possibly jagged matrix (an array of arrays).
Rows are padded with nulls so the result is always rectangular.
Example: transpose
Input: [[1], [2,3]]
Output: [[1,2],[null,3]]
----------------------------------------------------------------------------
`bsearch(x)`
----------------------------------------------------------------------------
`bsearch(x)` conducts a binary search for x in the input
array. If the input is sorted and contains x, then
`bsearch(x)` will return its index in the array; otherwise, if
the array is sorted, it will return (-1 - ix) where ix is an
insertion point such that the array would still be sorted
after the insertion of x at ix. If the array is not sorted,
`bsearch(x)` will return an integer that is probably of no
interest.
Example: bsearch(0)
Input: [0,1]
Output: 0
Example: bsearch(0)
Input: [1,2,3]
Output: -1
Example: bsearch(4) as $ix | if $ix < 0 then .[-(1+$ix)] = 4 else . end
Input: [1,2,3]
Output: [1,2,3,4]
----------------------------------------------------------------------------
String interpolation: `\(exp)`
----------------------------------------------------------------------------
Inside a string, you can put an expression inside parens
after a backslash. Whatever the expression returns will be
interpolated into the string.
Example: "The input was \(.), which is one less than \(.+1)"
Input: 42
Output: "The input was 42, which is one less than 43"
----------------------------------------------------------------------------
Convert to/from JSON
----------------------------------------------------------------------------
The `tojson` and `fromjson` builtins dump values as JSON texts
or parse JSON texts into values, respectively. The `tojson`
builtin differs from `tostring` in that `tostring` returns strings
unmodified, while `tojson` encodes strings as JSON strings.
Example: [.[]|tostring]
Input: [1, "foo", ["foo"]]
Output: ["1","foo","[\"foo\"]"]
Example: [.[]|tojson]
Input: [1, "foo", ["foo"]]
Output: ["1","\"foo\"","[\"foo\"]"]
Example: [.[]|tojson|fromjson]
Input: [1, "foo", ["foo"]]
Output: [1,"foo",["foo"]]
----------------------------------------------------------------------------
Format strings and escaping
----------------------------------------------------------------------------
The `@foo` syntax is used to format and escape strings,
which is useful for building URLs, documents in a language
like HTML or XML, and so forth. `@foo` can be used as a
filter on its own, the possible escapings are:
* `@text`:
Calls `tostring`, see that function for details.
* `@json`:
Serializes the input as JSON.
* `@html`:
Applies HTML/XML escaping, by mapping the characters
`<>&'"` to their entity equivalents `<`, `>`,
`&`, `'`, `"`.
* `@uri`:
Applies percent-encoding, by mapping all reserved URI
characters to a `%XX` sequence.
* `@urid`:
The inverse of `@uri`, applies percent-decoding, by mapping
all `%XX` sequences to their corresponding URI characters.
* `@csv`:
The input must be an array, and it is rendered as CSV
with double quotes for strings, and quotes escaped by
repetition.
* `@tsv`:
The input must be an array, and it is rendered as TSV
(tab-separated values). Each input array will be printed as
a single line. Fields are separated by a single
tab (ascii `0x09`). Input characters line-feed (ascii `0x0a`),
carriage-return (ascii `0x0d`), tab (ascii `0x09`) and
backslash (ascii `0x5c`) will be output as escape sequences
`\n`, `\r`, `\t`, `\\` respectively.
* `@sh`:
The input is escaped suitable for use in a command-line
for a POSIX shell. If the input is an array, the output
will be a series of space-separated strings.
* `@base64`:
The input is converted to base64 as specified by RFC 4648.
* `@base64d`:
The inverse of `@base64`, input is decoded as specified by RFC 4648.
Note\: If the decoded string is not UTF-8, the results are undefined.
This syntax can be combined with string interpolation in a
useful way. You can follow a `@foo` token with a string
literal. The contents of the string literal will *not* be
escaped. However, all interpolations made inside that string
literal will be escaped. For instance,
@uri "https://www.google.com/search?q=\(.search)"
will produce the following output for the input
`{"search":"what is jq?"}`:
"https://www.google.com/search?q=what%20is%20jq%3F"
Note that the slashes, question mark, etc. in the URL are
not escaped, as they were part of the string literal.
Example: @html
Input: "This works if x < y"
Output: "This works if x < y"
Example: @sh "echo \(.)"
Input: "O'Hara's Ale"
Output: "echo 'O'\\''Hara'\\''s Ale'"
Example: @base64
Input: "This is a message"
Output: "VGhpcyBpcyBhIG1lc3NhZ2U="
Example: @base64d
Input: "VGhpcyBpcyBhIG1lc3NhZ2U="
Output: "This is a message"
----------------------------------------------------------------------------
Dates
----------------------------------------------------------------------------
jq provides some basic date handling functionality, with some
high-level and low-level builtins. In all cases these
builtins deal exclusively with time in UTC.
The `fromdateiso8601` builtin parses datetimes in the ISO 8601
format to a number of seconds since the Unix epoch
(1970-01-01T00:00:00Z). The `todateiso8601` builtin does the
inverse.
The `fromdate` builtin parses datetime strings. Currently
`fromdate` only supports ISO 8601 datetime strings, but in the
future it will attempt to parse datetime strings in more
formats.
The `todate` builtin is an alias for `todateiso8601`.
The `now` builtin outputs the current time, in seconds since
the Unix epoch.
Low-level jq interfaces to the C-library time functions are
also provided: `strptime`, `strftime`, `strflocaltime`,
`mktime`, `gmtime`, and `localtime`. Refer to your host
operating system's documentation for the format strings used
by `strptime` and `strftime`. Note: these are not necessarily
stable interfaces in jq, particularly as to their localization
functionality.
The `gmtime` builtin consumes a number of seconds since the
Unix epoch and outputs a "broken down time" representation of
Greenwich Mean Time as an array of numbers representing
(in this order): the year, the month (zero-based), the day of
the month (one-based), the hour of the day, the minute of the
hour, the second of the minute, the day of the week, and the
day of the year -- all one-based unless otherwise stated. The
day of the week number may be wrong on some systems for dates
before March 1st 1900, or after December 31 2099.
The `localtime` builtin works like the `gmtime` builtin, but
using the local timezone setting.
The `mktime` builtin consumes "broken down time"
representations of time output by `gmtime` and `strptime`.
The `strptime(fmt)` builtin parses input strings matching the
`fmt` argument. The output is in the "broken down time"
representation consumed by `mktime` and output by `gmtime`.
The `strftime(fmt)` builtin formats a time (GMT) with the
given format. The `strflocaltime` does the same, but using
the local timezone setting.
The format strings for `strptime` and `strftime` are described
in typical C library documentation. The format string for ISO
8601 datetime is `"%Y-%m-%dT%H:%M:%SZ"`.
jq may not support some or all of this date functionality on
some systems. In particular, the `%u` and `%j` specifiers for
`strptime(fmt)` are not supported on macOS.
Example: fromdate
Input: "2015-03-05T23:51:47Z"
Output: 1425599507
Example: strptime("%Y-%m-%dT%H:%M:%SZ")
Input: "2015-03-05T23:51:47Z"
Output: [2015,2,5,23,51,47,4,63]
Example: strptime("%Y-%m-%dT%H:%M:%SZ")|mktime
Input: "2015-03-05T23:51:47Z"
Output: 1425599507
----------------------------------------------------------------------------
SQL-Style Operators
----------------------------------------------------------------------------
jq provides a few SQL-style operators.
* `INDEX(stream; index_expression)`:
This builtin produces an object whose keys are computed by
the given index expression applied to each value from the
given stream.
* `JOIN($idx; stream; idx_expr; join_expr)`:
This builtin joins the values from the given stream to the
given index. The index's keys are computed by applying the
given index expression to each value from the given stream.
An array of the value in the stream and the corresponding
value from the index is fed to the given join expression to
produce each result.
* `JOIN($idx; stream; idx_expr)`:
Same as `JOIN($idx; stream; idx_expr; .)`.
* `JOIN($idx; idx_expr)`:
This builtin joins the input `.` to the given index, applying
the given index expression to `.` to compute the index key.
The join operation is as described above.
* `IN(s)`:
This builtin outputs `true` if `.` appears in the given
stream, otherwise it outputs `false`.
* `IN(source; s)`:
This builtin outputs `true` if any value in the source stream
appears in the second stream, otherwise it outputs `false`.
----------------------------------------------------------------------------
`builtins`
----------------------------------------------------------------------------
Returns a list of all builtin functions in the format `name/arity`.
Since functions with the same name but different arities are considered
separate functions, `all/0`, `all/1`, and `all/2` would all be present
in the list.
============================================================================
SECTION: Conditionals and Comparisons
============================================================================
----------------------------------------------------------------------------
`==`, `!=`
----------------------------------------------------------------------------
The expression 'a == b' will produce 'true' if the results of evaluating
a and b are equal (that is, if they represent equivalent JSON values) and
'false' otherwise. In particular, strings are never considered equal
to numbers. In checking for the equality of JSON objects, the ordering of keys
is irrelevant. If you're coming from JavaScript, please note that jq's `==` is like
JavaScript's `===`, the "strict equality" operator.
!= is "not equal", and 'a != b' returns the opposite value of 'a == b'
Example: . == false
Input: null
Output: false
Example: . == {"b": {"d": (4 + 1e-20), "c": 3}, "a":1}
Input: {"a":1, "b": {"c": 3, "d": 4}}
Output: true
Example: .[] == 1
Input: [1, 1.0, "1", "banana"]
Output: true
true
false
false
----------------------------------------------------------------------------
if-then-else-end
----------------------------------------------------------------------------
`if A then B else C end` will act the same as `B` if `A`
produces a value other than false or null, but act the same
as `C` otherwise.
`if A then B end` is the same as `if A then B else . end`.
That is, the `else` branch is optional, and if absent is the
same as `.`. This also applies to `elif` with absent ending `else` branch.
Checking for false or null is a simpler notion of
"truthiness" than is found in JavaScript or Python, but it
means that you'll sometimes have to be more explicit about
the condition you want. You can't test whether, e.g. a
string is empty using `if .name then A else B end`; you'll
need something like `if .name == "" then A else B end` instead.
If the condition `A` produces multiple results, then `B` is evaluated
once for each result that is not false or null, and `C` is evaluated
once for each false or null.
More cases can be added to an if using `elif A then B` syntax.
Example: if . == 0 then
"zero"
elif . == 1 then
"one"
else
"many"
end
Input: 2
Output: "many"
----------------------------------------------------------------------------
`>`, `>=`, `<=`, `<`
----------------------------------------------------------------------------
The comparison operators `>`, `>=`, `<=`, `<` return whether
their left argument is greater than, greater than or equal
to, less than or equal to or less than their right argument
(respectively).
The ordering is the same as that described for `sort`, above.
Example: . < 5
Input: 2
Output: true
----------------------------------------------------------------------------
`and`, `or`, `not`
----------------------------------------------------------------------------
jq supports the normal Boolean operators `and`, `or`, `not`.
They have the same standard of truth as if expressions -
`false` and `null` are considered "false values", and
anything else is a "true value".
If an operand of one of these operators produces multiple
results, the operator itself will produce a result for each input.
`not` is in fact a builtin function rather than an operator,
so it is called as a filter to which things can be piped
rather than with special syntax, as in `.foo and .bar |
not`.
These three only produce the values `true` and `false`, and
so are only useful for genuine Boolean operations, rather
than the common Perl/Python/Ruby idiom of
"value_that_may_be_null or default". If you want to use this
form of "or", picking between two values rather than
evaluating a condition, see the `//` operator below.
Example: 42 and "a string"
Input: null
Output: true
Example: (true, false) or false
Input: null
Output: true
false
Example: (true, true) and (true, false)
Input: null
Output: true
false
true
false
Example: [true, false | not]
Input: null
Output: [false, true]
----------------------------------------------------------------------------
Alternative operator: `//`
----------------------------------------------------------------------------
The `//` operator produces all the values of its left-hand
side that are neither `false` nor `null`. If the
left-hand side produces no values other than `false` or
`null`, then `//` produces all the values of its right-hand
side.
A filter of the form `a // b` produces all the results of
`a` that are not `false` or `null`. If `a` produces no
results, or no results other than `false` or `null`, then `a
// b` produces the results of `b`.
This is useful for providing defaults: `.foo // 1` will
evaluate to `1` if there's no `.foo` element in the
input. It's similar to how `or` is sometimes used in Python
(jq's `or` operator is reserved for strictly Boolean
operations).
Note: `some_generator // defaults_here` is not the same
as `some_generator | . // defaults_here`. The latter will
produce default values for all non-`false`, non-`null`
values of the left-hand side, while the former will not.
Precedence rules can make this confusing. For example, in
`false, 1 // 2` the left-hand side of `//` is `1`, not
`false, 1` -- `false, 1 // 2` parses the same way as `false,
(1 // 2)`. In `(false, null, 1) | . // 42` the left-hand
side of `//` is `.`, which always produces just one value,
while in `(false, null, 1) // 42` the left-hand side is a
generator of three values, and since it produces a
value other `false` and `null`, the default `42` is not
produced.
Example: empty // 42
Input: null
Output: 42
Example: .foo // 42
Input: {"foo": 19}
Output: 19
Example: .foo // 42
Input: {}
Output: 42
Example: (false, null, 1) // 42
Input: null
Output: 1
Example: (false, null, 1) | . // 42
Input: null
Output: 42
42
1
----------------------------------------------------------------------------
try-catch
----------------------------------------------------------------------------
Errors can be caught by using `try EXP catch EXP`. The first
expression is executed, and if it fails then the second is
executed with the error message. The output of the handler,
if any, is output as if it had been the output of the
expression to try.
The `try EXP` form uses `empty` as the exception handler.
Example: try .a catch ". is not an object"
Input: true
Output: ". is not an object"
Example: [.[]|try .a]
Input: [{}, true, {"a":1}]
Output: [null, 1]
Example: try error("some exception") catch .
Input: true
Output: "some exception"
----------------------------------------------------------------------------
Breaking out of control structures
----------------------------------------------------------------------------
A convenient use of try/catch is to break out of control
structures like `reduce`, `foreach`, `while`, and so on.
For example:
# Repeat an expression until it raises "break" as an
# error, then stop repeating without re-raising the error.
# But if the error caught is not "break" then re-raise it.
try repeat(exp) catch if .=="break" then empty else error
jq has a syntax for named lexical labels to "break" or "go (back) to":
label $out | ... break $out ...
The `break $label_name` expression will cause the program to
act as though the nearest (to the left) `label $label_name`
produced `empty`.
The relationship between the `break` and corresponding `label`
is lexical: the label has to be "visible" from the break.
To break out of a `reduce`, for example:
label $out | reduce .[] as $item (null; if .==false then break $out else ... end)
The following jq program produces a syntax error:
break $out
because no label `$out` is visible.
----------------------------------------------------------------------------
Error Suppression / Optional Operator: `?`
----------------------------------------------------------------------------
The `?` operator, used as `EXP?`, is shorthand for `try EXP`.
Example: [.[] | .a?]
Input: [{}, true, {"a":1}]
Output: [null, 1]
Example: [.[] | tonumber?]
Input: ["1", "invalid", "3", 4]
Output: [1, 3, 4]
============================================================================
SECTION: Regular expressions
============================================================================
jq uses the
[Oniguruma regular expression library](https://github.com/kkos/oniguruma/blob/master/doc/RE),
as do PHP, TextMate, Sublime Text, etc, so the
description here will focus on jq specifics.
Oniguruma supports several flavors of regular expression, so it is important to know
that jq uses the ["Perl NG" (Perl with named groups)](https://github.com/kkos/oniguruma/blob/master/doc/SYNTAX.md) flavor.
The jq regex filters are defined so that they can be used using
one of these patterns:
STRING | FILTER(REGEX)
STRING | FILTER(REGEX; FLAGS)
STRING | FILTER([REGEX])
STRING | FILTER([REGEX, FLAGS])
where:
* STRING, REGEX, and FLAGS are jq strings and subject to jq string interpolation;
* REGEX, after string interpolation, should be a valid regular expression;
* FILTER is one of `test`, `match`, or `capture`, as described below.
Since REGEX must evaluate to a JSON string, some characters that are needed
to form a regular expression must be escaped. For example, the regular expression
`\s` signifying a whitespace character would be written as `"\\s"`.
FLAGS is a string consisting of one of more of the supported flags:
* `g` - Global search (find all matches, not just the first)
* `i` - Case insensitive search
* `m` - Multi line mode (`.` will match newlines)
* `n` - Ignore empty matches
* `p` - Both s and m modes are enabled
* `s` - Single line mode (`^` -> `\A`, `$` -> `\Z`)
* `l` - Find longest possible matches
* `x` - Extended regex format (ignore whitespace and comments)
To match a whitespace with the `x` flag, use `\s`, e.g.
jq -n '"a b" | test("a\\sb"; "x")'
Note that certain flags may also be specified within REGEX, e.g.
jq -n '("test", "TEst", "teST", "TEST") | test("(?i)te(?-i)st")'
evaluates to: `true`, `true`, `false`, `false`.
----------------------------------------------------------------------------
`test(val)`, `test(regex; flags)`
----------------------------------------------------------------------------
Like `match`, but does not return match objects, only `true` or `false`
for whether or not the regex matches the input.
Example: test("foo")
Input: "foo"
Output: true
Example: .[] | test("a b c # spaces are ignored"; "ix")
Input: ["xabcd", "ABC"]
Output: true
true
----------------------------------------------------------------------------
`match(val)`, `match(regex; flags)`
----------------------------------------------------------------------------
**match** outputs an object for each match it finds. Matches have
the following fields:
* `offset` - offset in UTF-8 codepoints from the beginning of the input
* `length` - length in UTF-8 codepoints of the match
* `string` - the string that it matched
* `captures` - an array of objects representing capturing groups.
Capturing group objects have the following fields:
* `offset` - offset in UTF-8 codepoints from the beginning of the input
* `length` - length in UTF-8 codepoints of this capturing group
* `string` - the string that was captured
* `name` - the name of the capturing group (or `null` if it was unnamed)
Capturing groups that did not match anything return an offset of -1
Example: match("(abc)+"; "g")
Input: "abc abc"
Output: {"offset": 0, "length": 3, "string": "abc", "captures": [{"offset": 0, "length": 3, "string": "abc", "name": null}]}
{"offset": 4, "length": 3, "string": "abc", "captures": [{"offset": 4, "length": 3, "string": "abc", "name": null}]}
Example: match("foo")
Input: "foo bar foo"
Output: {"offset": 0, "length": 3, "string": "foo", "captures": []}
Example: match(["foo", "ig"])
Input: "foo bar FOO"
Output: {"offset": 0, "length": 3, "string": "foo", "captures": []}
{"offset": 8, "length": 3, "string": "FOO", "captures": []}
Example: match("foo (?<bar123>bar)? foo"; "ig")
Input: "foo bar foo foo foo"
Output: {"offset": 0, "length": 11, "string": "foo bar foo", "captures": [{"offset": 4, "length": 3, "string": "bar", "name": "bar123"}]}
{"offset": 12, "length": 8, "string": "foo foo", "captures": [{"offset": -1, "length": 0, "string": null, "name": "bar123"}]}
Example: [ match("."; "g")] | length
Input: "abc"
Output: 3
----------------------------------------------------------------------------
`capture(val)`, `capture(regex; flags)`
----------------------------------------------------------------------------
Collects the named captures in a JSON object, with the name
of each capture as the key, and the matched string as the
corresponding value.
Example: capture("(?<a>[a-z]+)-(?<n>[0-9]+)")
Input: "xyzzy-14"
Output: { "a": "xyzzy", "n": "14" }
----------------------------------------------------------------------------
`scan(regex)`, `scan(regex; flags)`
----------------------------------------------------------------------------
Emit a stream of the non-overlapping substrings of the input
that match the regex in accordance with the flags, if any
have been specified. If there is no match, the stream is empty.
To capture all the matches for each input string, use the idiom
`[ expr ]`, e.g. `[ scan(regex) ]`. If the regex contains capturing
groups, the filter emits a stream of arrays, each of which contains
the captured strings.
Example: scan("c")
Input: "abcdefabc"
Output: "c"
"c"
Example: scan("(a+)(b+)")
Input: "abaabbaaabbb"
Output: ["a","b"]
["aa","bb"]
["aaa","bbb"]
----------------------------------------------------------------------------
`split(regex; flags)`
----------------------------------------------------------------------------
Splits an input string on each regex match.
For backwards compatibility, when called with a single argument,
`split` splits on a string, not a regex.
Example: split(", *"; null)
Input: "ab,cd, ef"
Output: ["ab","cd","ef"]
----------------------------------------------------------------------------
`splits(regex)`, `splits(regex; flags)`
----------------------------------------------------------------------------
These provide the same results as their `split` counterparts,
but as a stream instead of an array.
Example: splits(", *")
Input: "ab,cd, ef, gh"
Output: "ab"
"cd"
"ef"
"gh"
Example: splits(",? *"; "n")
Input: "ab,cd ef, gh"
Output: "ab"
"cd"
"ef"
"gh"
----------------------------------------------------------------------------
`sub(regex; tostring)`, `sub(regex; tostring; flags)`
----------------------------------------------------------------------------
Emit the string obtained by replacing the first match of
regex in the input string with `tostring`, after
interpolation. `tostring` should be a jq string or a stream
of such strings, each of which may contain references to
named captures. The named captures are, in effect, presented
as a JSON object (as constructed by `capture`) to
`tostring`, so a reference to a captured variable named "x"
would take the form: `"\(.x)"`.
Example: sub("[^a-z]*(?<x>[a-z]+)"; "Z\(.x)"; "g")
Input: "123abc456def"
Output: "ZabcZdef"
Example: [sub("(?<a>.)"; "\(.a|ascii_upcase)", "\(.a|ascii_downcase)")]
Input: "aB"
Output: ["AB","aB"]
----------------------------------------------------------------------------
`gsub(regex; tostring)`, `gsub(regex; tostring; flags)`
----------------------------------------------------------------------------
`gsub` is like `sub` but all the non-overlapping occurrences of the regex are
replaced by `tostring`, after interpolation. If the second argument is a stream
of jq strings, then `gsub` will produce a corresponding stream of JSON strings.
Example: gsub("(?<x>.)[^a]*"; "+\(.x)-")
Input: "Abcabc"
Output: "+A-+a-"
Example: [gsub("p"; "a", "b")]
Input: "p"
Output: ["a","b"]
============================================================================
SECTION: Advanced features
============================================================================
Variables are an absolute necessity in most programming languages, but
they're relegated to an "advanced feature" in jq.
In most languages, variables are the only means of passing around
data. If you calculate a value, and you want to use it more than once,
you'll need to store it in a variable. To pass a value to another part
of the program, you'll need that part of the program to define a
variable (as a function parameter, object member, or whatever) in
which to place the data.
It is also possible to define functions in jq, although this is
is a feature whose biggest use is defining jq's standard library
(many jq functions such as `map` and `select` are in fact written
in jq).
jq has reduction operators, which are very powerful but a bit
tricky. Again, these are mostly used internally, to define some
useful bits of jq's standard library.
It may not be obvious at first, but jq is all about generators
(yes, as often found in other languages). Some utilities are
provided to help deal with generators.
Some minimal I/O support (besides reading JSON from standard
input, and writing JSON to standard output) is available.
Finally, there is a module/library system.
----------------------------------------------------------------------------
Variable / Symbolic Binding Operator: `... as $identifier | ...`
----------------------------------------------------------------------------
In jq, all filters have an input and an output, so manual
plumbing is not necessary to pass a value from one part of a program
to the next. Many expressions, for instance `a + b`, pass their input
to two distinct subexpressions (here `a` and `b` are both passed the
same input), so variables aren't usually necessary in order to use a
value twice.
For instance, calculating the average value of an array of numbers
requires a few variables in most languages - at least one to hold the
array, perhaps one for each element or for a loop counter. In jq, it's
simply `add / length` - the `add` expression is given the array and
produces its sum, and the `length` expression is given the array and
produces its length.
So, there's generally a cleaner way to solve most problems in jq than
defining variables. Still, sometimes they do make things easier, so jq
lets you define variables using `expression as $variable`. All
variable names start with `$`. Here's a slightly uglier version of the
array-averaging example:
length as $array_length | add / $array_length
We'll need a more complicated problem to find a situation where using
variables actually makes our lives easier.
Suppose we have an array of blog posts, with "author" and "title"
fields, and another object which is used to map author usernames to
real names. Our input looks like:
{"posts": [{"title": "First post", "author": "anon"},
{"title": "A well-written article", "author": "person1"}],
"realnames": {"anon": "Anonymous Coward",
"person1": "Person McPherson"}}
We want to produce the posts with the author field containing a real
name, as in:
{"title": "First post", "author": "Anonymous Coward"}
{"title": "A well-written article", "author": "Person McPherson"}
We use a variable, `$names`, to store the realnames object, so that we
can refer to it later when looking up author usernames:
.realnames as $names | .posts[] | {title, author: $names[.author]}
The expression `exp as $x | ...` means: for each value of expression
`exp`, run the rest of the pipeline with the entire original input, and
with `$x` set to that value. Thus `as` functions as something of a
foreach loop.
Just as `{foo}` is a handy way of writing `{foo: .foo}`, so
`{$foo}` is a handy way of writing `{foo: $foo}`.
Multiple variables may be declared using a single `as` expression by
providing a pattern that matches the structure of the input
(this is known as "destructuring"):
. as {realnames: $names, posts: [$first, $second]} | ...
The variable declarations in array patterns (e.g., `. as
[$first, $second]`) bind to the elements of the array in from
the element at index zero on up, in order. When there is no
value at the index for an array pattern element, `null` is
bound to that variable.
Variables are scoped over the rest of the expression that defines
them, so
.realnames as $names | (.posts[] | {title, author: $names[.author]})
will work, but
(.realnames as $names | .posts[]) | {title, author: $names[.author]}
won't.
For programming language theorists, it's more accurate to
say that jq variables are lexically-scoped bindings. In
particular there's no way to change the value of a binding;
one can only setup a new binding with the same name, but which
will not be visible where the old one was.
Example: .bar as $x | .foo | . + $x
Input: {"foo":10, "bar":200}
Output: 210
Example: . as $i|[(.*2|. as $i| $i), $i]
Input: 5
Output: [10,5]
Example: . as [$a, $b, {c: $c}] | $a + $b + $c
Input: [2, 3, {"c": 4, "d": 5}]
Output: 9
Example: .[] as [$a, $b] | {a: $a, b: $b}
Input: [[0], [0, 1], [2, 1, 0]]
Output: {"a":0,"b":null}
{"a":0,"b":1}
{"a":2,"b":1}
----------------------------------------------------------------------------
Destructuring Alternative Operator: `?//`
----------------------------------------------------------------------------
The destructuring alternative operator provides a concise mechanism
for destructuring an input that can take one of several forms.
Suppose we have an API that returns a list of resources and events
associated with them, and we want to get the user_id and timestamp of
the first event for each resource. The API (having been clumsily
converted from XML) will only wrap the events in an array if the resource
has multiple events:
{"resources": [{"id": 1, "kind": "widget", "events": {"action": "create", "user_id": 1, "ts": 13}},
{"id": 2, "kind": "widget", "events": [{"action": "create", "user_id": 1, "ts": 14}, {"action": "destroy", "user_id": 1, "ts": 15}]}]}
We can use the destructuring alternative operator to handle this structural change simply:
.resources[] as {$id, $kind, events: {$user_id, $ts}} ?// {$id, $kind, events: [{$user_id, $ts}]} | {$user_id, $kind, $id, $ts}
Or, if we aren't sure if the input is an array of values or an object:
.[] as [$id, $kind, $user_id, $ts] ?// {$id, $kind, $user_id, $ts} | ...
Each alternative need not define all of the same variables, but all named
variables will be available to the subsequent expression. Variables not
matched in the alternative that succeeded will be `null`:
.resources[] as {$id, $kind, events: {$user_id, $ts}} ?// {$id, $kind, events: [{$first_user_id, $first_ts}]} | {$user_id, $first_user_id, $kind, $id, $ts, $first_ts}
Additionally, if the subsequent expression returns an error, the
alternative operator will attempt to try the next binding. Errors
that occur during the final alternative are passed through.
[[3]] | .[] as [$a] ?// [$b] | if $a != null then error("err: \($a)") else {$a,$b} end
Example: .[] as {$a, $b, c: {$d, $e}} ?// {$a, $b, c: [{$d, $e}]} | {$a, $b, $d, $e}
Input: [{"a": 1, "b": 2, "c": {"d": 3, "e": 4}}, {"a": 1, "b": 2, "c": [{"d": 3, "e": 4}]}]
Output: {"a":1,"b":2,"d":3,"e":4}
{"a":1,"b":2,"d":3,"e":4}
Example: .[] as {$a, $b, c: {$d}} ?// {$a, $b, c: [{$e}]} | {$a, $b, $d, $e}
Input: [{"a": 1, "b": 2, "c": {"d": 3, "e": 4}}, {"a": 1, "b": 2, "c": [{"d": 3, "e": 4}]}]
Output: {"a":1,"b":2,"d":3,"e":null}
{"a":1,"b":2,"d":null,"e":4}
Example: .[] as [$a] ?// [$b] | if $a != null then error("err: \($a)") else {$a,$b} end
Input: [[3]]
Output: {"a":null,"b":3}
----------------------------------------------------------------------------
Defining Functions
----------------------------------------------------------------------------
You can give a filter a name using "def" syntax:
def increment: . + 1;
From then on, `increment` is usable as a filter just like a
builtin function (in fact, this is how many of the builtins
are defined). A function may take arguments:
def map(f): [.[] | f];
Arguments are passed as _filters_ (functions with no
arguments), _not_ as values. The same argument may be
referenced multiple times with different inputs (here `f` is
run for each element of the input array). Arguments to a
function work more like callbacks than like value arguments.
This is important to understand. Consider:
def foo(f): f|f;
5|foo(.*2)
The result will be 20 because `f` is `.*2`, and during the
first invocation of `f` `.` will be 5, and the second time it
will be 10 (5 * 2), so the result will be 20. Function
arguments are filters, and filters expect an input when
invoked.
If you want the value-argument behaviour for defining simple
functions, you can just use a variable:
def addvalue(f): f as $f | map(. + $f);
Or use the short-hand:
def addvalue($f): ...;
With either definition, `addvalue(.foo)` will add the current
input's `.foo` field to each element of the array. Do note
that calling `addvalue(.[])` will cause the `map(. + $f)` part
to be evaluated once per value in the value of `.` at the call
site.
Multiple definitions using the same function name are allowed.
Each re-definition replaces the previous one for the same
number of function arguments, but only for references from
functions (or main program) subsequent to the re-definition.
See also the section below on scoping.
Example: def addvalue(f): . + [f]; map(addvalue(.[0]))
Input: [[1,2],[10,20]]
Output: [[1,2,1], [10,20,10]]
Example: def addvalue(f): f as $x | map(. + $x); addvalue(.[0])
Input: [[1,2],[10,20]]
Output: [[1,2,1,2], [10,20,1,2]]
----------------------------------------------------------------------------
Scoping
----------------------------------------------------------------------------
There are two types of symbols in jq: value bindings (a.k.a.,
"variables"), and functions. Both are scoped lexically,
with expressions being able to refer only to symbols that
have been defined "to the left" of them. The only exception
to this rule is that functions can refer to themselves so as
to be able to create recursive functions.
For example, in the following expression there is a binding
which is visible "to the right" of it, `... | .*3 as
$times_three | [. + $times_three] | ...`, but not "to the
left". Consider this expression now, `... | (.*3 as
$times_three | [. + $times_three]) | ...`: here the binding
`$times_three` is _not_ visible past the closing parenthesis.
----------------------------------------------------------------------------
`isempty(exp)`
----------------------------------------------------------------------------
Returns true if `exp` produces no outputs, false otherwise.
Example: isempty(empty)
Input: null
Output: true
Example: isempty(.[])
Input: []
Output: true
Example: isempty(.[])
Input: [1,2,3]
Output: false
----------------------------------------------------------------------------
`limit(n; expr)`
----------------------------------------------------------------------------
The `limit` function extracts up to `n` outputs from `expr`.
Example: [limit(3; .[])]
Input: [0,1,2,3,4,5,6,7,8,9]
Output: [0,1,2]
----------------------------------------------------------------------------
`skip(n; expr)`
----------------------------------------------------------------------------
The `skip` function skips the first `n` outputs from `expr`.
Example: [skip(3; .[])]
Input: [0,1,2,3,4,5,6,7,8,9]
Output: [3,4,5,6,7,8,9]
----------------------------------------------------------------------------
`first(expr)`, `last(expr)`, `nth(n; expr)`
----------------------------------------------------------------------------
The `first(expr)` and `last(expr)` functions extract the first
and last values from `expr`, respectively.
The `nth(n; expr)` function extracts the nth value output by `expr`.
Note that `nth(n; expr)` doesn't support negative values of `n`.
Example: [first(range(.)), last(range(.)), nth(5; range(.))]
Input: 10
Output: [0,9,5]
Example: [first(empty), last(empty), nth(5; empty)]
Input: null
Output: []
----------------------------------------------------------------------------
`first`, `last`, `nth(n)`
----------------------------------------------------------------------------
The `first` and `last` functions extract the first
and last values from any array at `.`.
The `nth(n)` function extracts the nth value of any array at `.`.
Example: [range(.)]|[first, last, nth(5)]
Input: 10
Output: [0,9,5]
----------------------------------------------------------------------------
`reduce`
----------------------------------------------------------------------------
The `reduce` syntax allows you to combine all of the results of
an expression by accumulating them into a single answer.
The form is `reduce EXP as $var (INIT; UPDATE)`.
As an example, we'll pass `[1,2,3]` to this expression:
reduce .[] as $item (0; . + $item)
For each result that `.[]` produces, `. + $item` is run to
accumulate a running total, starting from 0 as the input value.
In this example, `.[]` produces the results `1`, `2`, and `3`,
so the effect is similar to running something like this:
0 | 1 as $item | . + $item |
2 as $item | . + $item |
3 as $item | . + $item
Example: reduce .[] as $item (0; . + $item)
Input: [1,2,3,4,5]
Output: 15
Example: reduce .[] as [$i,$j] (0; . + $i * $j)
Input: [[1,2],[3,4],[5,6]]
Output: 44
Example: reduce .[] as {$x,$y} (null; .x += $x | .y += [$y])
Input: [{"x":"a","y":1},{"x":"b","y":2},{"x":"c","y":3}]
Output: {"x":"abc","y":[1,2,3]}
----------------------------------------------------------------------------
`foreach`
----------------------------------------------------------------------------
The `foreach` syntax is similar to `reduce`, but intended to
allow the construction of `limit` and reducers that produce
intermediate results.
The form is `foreach EXP as $var (INIT; UPDATE; EXTRACT)`.
As an example, we'll pass `[1,2,3]` to this expression:
foreach .[] as $item (0; . + $item; [$item, . * 2])
Like the `reduce` syntax, `. + $item` is run for each result
that `.[]` produces, but `[$item, . * 2]` is run for each
intermediate values. In this example, since the intermediate
values are `1`, `3`, and `6`, the `foreach` expression produces
`[1,2]`, `[2,6]`, and `[3,12]`. So the effect is similar
to running something like this:
0 | 1 as $item | . + $item | [$item, . * 2],
2 as $item | . + $item | [$item, . * 2],
3 as $item | . + $item | [$item, . * 2]
When `EXTRACT` is omitted, the identity filter is used.
That is, it outputs the intermediate values as they are.
Example: foreach .[] as $item (0; . + $item)
Input: [1,2,3,4,5]
Output: 1
3
6
10
15
Example: foreach .[] as $item (0; . + $item; [$item, . * 2])
Input: [1,2,3,4,5]
Output: [1,2]
[2,6]
[3,12]
[4,20]
[5,30]
Example: foreach .[] as $item (0; . + 1; {index: ., $item})
Input: ["foo", "bar", "baz"]
Output: {"index":1,"item":"foo"}
{"index":2,"item":"bar"}
{"index":3,"item":"baz"}
----------------------------------------------------------------------------
Recursion
----------------------------------------------------------------------------
As described above, `recurse` uses recursion, and any jq
function can be recursive. The `while` builtin is also
implemented in terms of recursion.
Tail calls are optimized whenever the expression to the left of
the recursive call outputs its last value. In practice this
means that the expression to the left of the recursive call
should not produce more than one output for each input.
For example:
def recurse(f): def r: ., (f | select(. != null) | r); r;
def while(cond; update):
def _while:
if cond then ., (update | _while) else empty end;
_while;
def repeat(exp):
def _repeat:
exp, _repeat;
_repeat;
----------------------------------------------------------------------------
Generators and iterators
----------------------------------------------------------------------------
Some jq operators and functions are actually generators in
that they can produce zero, one, or more values for each
input, just as one might expect in other programming
languages that have generators. For example, `.[]`
generates all the values in its input (which must be an
array or an object), `range(0; 10)` generates the integers
between 0 and 10, and so on.
Even the comma operator is a generator, generating first
the values generated by the expression to the left of the
comma, then the values generated by the expression on the
right of the comma.
The `empty` builtin is the generator that produces zero
outputs. The `empty` builtin backtracks to the preceding
generator expression.
All jq functions can be generators just by using builtin
generators. It is also possible to construct new generators
using only recursion and the comma operator. If
recursive calls are "in tail position" then the
generator will be efficient. In the example below the
recursive call by `_range` to itself is in tail position.
The example shows off three advanced topics: tail recursion,
generator construction, and sub-functions.
Example: def range(init; upto; by): def _range: if (by > 0 and . < upto) or (by < 0 and . > upto) then ., ((.+by)|_range) else empty end; if init == upto then empty elif by == 0 then init else init|_range end; range(0; 10; 3)
Input: null
Output: 0
3
6
9
Example: def while(cond; update): def _while: if cond then ., (update | _while) else empty end; _while; [while(.<100; .*2)]
Input: 1
Output: [1,2,4,8,16,32,64]
============================================================================
SECTION: Math
============================================================================
jq currently only has IEEE754 double-precision (64-bit) floating
point number support.
Besides simple arithmetic operators such as `+`, jq also has most
standard math functions from the C math library. C math functions
that take a single input argument (e.g., `sin()`) are available as
zero-argument jq functions. C math functions that take two input
arguments (e.g., `pow()`) are available as two-argument jq
functions that ignore `.`. C math functions that take three input
arguments are available as three-argument jq functions that ignore
`.`.
Availability of standard math functions depends on the
availability of the corresponding math functions in your operating
system and C math library. Unavailable math functions will be
defined but will raise an error.
One-input C math functions: `acos` `acosh` `asin` `asinh` `atan`
`atanh` `cbrt` `ceil` `cos` `cosh` `erf` `erfc` `exp` `exp10`
`exp2` `expm1` `fabs` `floor` `gamma` `j0` `j1` `lgamma` `log`
`log10` `log1p` `log2` `logb` `nearbyint` `rint` `round`
`significand` `sin` `sinh` `sqrt` `tan` `tanh` `tgamma` `trunc`
`y0` `y1`.
Two-input C math functions: `atan2` `copysign` `drem` `fdim`
`fmax` `fmin` `fmod` `frexp` `hypot` `jn` `ldexp` `modf`
`nextafter` `nexttoward` `pow` `remainder` `scalb` `scalbln` `yn`.
Three-input C math functions: `fma`.
See your system's manual for more information on each of these.
============================================================================
SECTION: I/O
============================================================================
At this time jq has minimal support for I/O, mostly in the
form of control over when inputs are read. Two builtins functions
are provided for this, `input` and `inputs`, that read from the
same sources (e.g., `stdin`, files named on the command-line) as
jq itself. These two builtins, and jq's own reading actions, can
be interleaved with each other. They are commonly used in combination
with the null input option `-n` to prevent one input from being read
implicitly.
Two builtins provide minimal output capabilities, `debug`, and
`stderr`. (Recall that a jq program's output values are always
output as JSON texts on `stdout`.) The `debug` builtin can have
application-specific behavior, such as for executables that use
the libjq C API but aren't the jq executable itself. The `stderr`
builtin outputs its input in raw mode to stderr with no additional
decoration, not even a newline.
Most jq builtins are referentially transparent, and yield constant
and repeatable value streams when applied to constant inputs.
This is not true of I/O builtins.
----------------------------------------------------------------------------
`input`
----------------------------------------------------------------------------
Outputs one new input.
Note that when using `input` it is generally necessary to
invoke jq with the `-n` command-line option, otherwise
the first entity will be lost.
echo 1 2 3 4 | jq '[., input]' # [1,2] [3,4]
----------------------------------------------------------------------------
`inputs`
----------------------------------------------------------------------------
Outputs all remaining inputs, one by one.
This is primarily useful for reductions over a program's
inputs. Note that when using `inputs` it is generally necessary
to invoke jq with the `-n` command-line option, otherwise
the first entity will be lost.
echo 1 2 3 | jq -n 'reduce inputs as $i (0; . + $i)' # 6
----------------------------------------------------------------------------
`debug`, `debug(msgs)`
----------------------------------------------------------------------------
These two filters are like `.` but have as a side-effect the
production of one or more messages on stderr.
The message produced by the `debug` filter has the form
["DEBUG:",<input-value>]
where `<input-value>` is a compact rendition of the input
value. This format may change in the future.
The `debug(msgs)` filter is defined as `(msgs | debug | empty), .`
thus allowing great flexibility in the content of the message,
while also allowing multi-line debugging statements to be created.
For example, the expression:
1 as $x | 2 | debug("Entering function foo with $x == \($x)", .) | (.+1)
would produce the value 3 but with the following two lines
being written to stderr:
["DEBUG:","Entering function foo with $x == 1"]
["DEBUG:",2]
----------------------------------------------------------------------------
`stderr`
----------------------------------------------------------------------------
Prints its input in raw and compact mode to stderr with no
additional decoration, not even a newline.
----------------------------------------------------------------------------
`input_filename`
----------------------------------------------------------------------------
Returns the name of the file whose input is currently being
filtered. Note that this will not work well unless jq is
running in a UTF-8 locale.
----------------------------------------------------------------------------
`input_line_number`
----------------------------------------------------------------------------
Returns the line number of the input currently being filtered.
============================================================================
SECTION: Streaming
============================================================================
With the `--stream` option jq can parse input texts in a streaming
fashion, allowing jq programs to start processing large JSON texts
immediately rather than after the parse completes. If you have a
single JSON text that is 1GB in size, streaming it will allow you
to process it much more quickly.
However, streaming isn't easy to deal with as the jq program will
have `[<path>, <leaf-value>]` (and a few other forms) as inputs.
Several builtins are provided to make handling streams easier.
The examples below use the streamed form of `["a",["b"]]`, which is
`[[0],"a"],[[1,0],"b"],[[1,0]],[[1]]`.
Streaming forms include `[<path>, <leaf-value>]` (to indicate any
scalar value, empty array, or empty object), and `[<path>]` (to
indicate the end of an array or object). Future versions of jq
run with `--stream` and `--seq` may output additional forms such
as `["error message"]` when an input text fails to parse.
----------------------------------------------------------------------------
`truncate_stream(stream_expression)`
----------------------------------------------------------------------------
Consumes a number as input and truncates the corresponding
number of path elements from the left of the outputs of the
given streaming expression.
Example: truncate_stream([[0],"a"],[[1,0],"b"],[[1,0]],[[1]])
Input: 1
Output: [[0],"b"]
[[0]]
----------------------------------------------------------------------------
`fromstream(stream_expression)`
----------------------------------------------------------------------------
Outputs values corresponding to the stream expression's
outputs.
Example: fromstream(1|truncate_stream([[0],"a"],[[1,0],"b"],[[1,0]],[[1]]))
Input: null
Output: ["b"]
----------------------------------------------------------------------------
`tostream`
----------------------------------------------------------------------------
The `tostream` builtin outputs the streamed form of its input.
Example: . as $dot|fromstream($dot|tostream)|.==$dot
Input: [0,[1,{"a":1},{"b":2}]]
Output: true
============================================================================
SECTION: Assignment
============================================================================
Assignment works a little differently in jq than in most
programming languages. jq doesn't distinguish between references
to and copies of something - two objects or arrays are either
equal or not equal, without any further notion of being "the
same object" or "not the same object".
If an object has two fields which are arrays, `.foo` and `.bar`,
and you append something to `.foo`, then `.bar` will not get
bigger, even if you've previously set `.bar = .foo`. If you're
used to programming in languages like Python, Java, Ruby,
JavaScript, etc. then you can think of it as though jq does a full
deep copy of every object before it does the assignment (for
performance it doesn't actually do that, but that's the general
idea).
This means that it's impossible to build circular values in jq
(such as an array whose first element is itself). This is quite
intentional, and ensures that anything a jq program can produce
can be represented in JSON.
All the assignment operators in jq have path expressions on the
left-hand side (LHS). The right-hand side (RHS) provides values
to set to the paths named by the LHS path expressions.
Values in jq are always immutable. Internally, assignment works
by using a reduction to compute new, replacement values for `.` that
have had all the desired assignments applied to `.`, then
outputting the modified value. This might be made clear by this
example: `{a:{b:{c:1}}} | (.a.b|=3), .`. This will output
`{"a":{"b":3}}` and `{"a":{"b":{"c":1}}}` because the last
sub-expression, `.`, sees the original value, not the modified
value.
Most users will want to use modification assignment operators,
such as `|=` or `+=`, rather than `=`.
Note that the LHS of assignment operators refers to a value in
`.`. Thus `$var.foo = 1` won't work as expected (`$var.foo` is
not a valid or useful path expression in `.`); use `$var | .foo =
1` instead.
Note too that `.a,.b=0` does not set `.a` and `.b`, but
`(.a,.b)=0` sets both.
----------------------------------------------------------------------------
Update-assignment: `|=`
----------------------------------------------------------------------------
This is the "update" operator `|=`. It takes a filter on the
right-hand side and works out the new value for the property
of `.` being assigned to by running the old value through this
expression. For instance, `(.foo, .bar) |= .+1` will build an
object with the `foo` field set to the input's `foo` plus 1,
and the `bar` field set to the input's `bar` plus 1.
The left-hand side can be any general path expression; see `path()`.
Note that the left-hand side of `|=` refers to a value in `.`.
Thus `$var.foo |= . + 1` won't work as expected (`$var.foo` is
not a valid or useful path expression in `.`); use `$var |
.foo |= . + 1` instead.
If the right-hand side outputs no values (i.e., `empty`), then
the left-hand side path will be deleted, as with `del(path)`.
If the right-hand side outputs multiple values, only the first
one will be used (COMPATIBILITY NOTE: in jq 1.5 and earlier
releases, it used to be that only the last one was used).
Example: (..|select(type=="boolean")) |= if . then 1 else 0 end
Input: [true,false,[5,true,[true,[false]],false]]
Output: [1,0,[5,1,[1,[0]],0]]
----------------------------------------------------------------------------
Arithmetic update-assignment: `+=`, `-=`, `*=`, `/=`, `%=`, `//=`
----------------------------------------------------------------------------
jq has a few operators of the form `a op= b`, which are all
equivalent to `a |= . op b`. So, `+= 1` can be used to
increment values, being the same as `|= . + 1`.
Example: .foo += 1
Input: {"foo": 42}
Output: {"foo": 43}
----------------------------------------------------------------------------
Plain assignment: `=`
----------------------------------------------------------------------------
This is the plain assignment operator. Unlike the others, the
input to the right-hand side (RHS) is the same as the input to
the left-hand side (LHS) rather than the value at the LHS
path, and all values output by the RHS will be used (as shown
below).
If the RHS of `=` produces multiple values, then for each such
value jq will set the paths on the left-hand side to the value
and then it will output the modified `.`. For example,
`(.a,.b) = range(2)` outputs `{"a":0,"b":0}`, then
`{"a":1,"b":1}`. The "update" assignment forms (see above) do
not do this.
This example should show the difference between `=` and `|=`:
Provide input `{"a": {"b": 10}, "b": 20}` to the programs
.a = .b
and
.a |= .b
The former will set the `a` field of the input to the `b`
field of the input, and produce the output `{"a": 20, "b": 20}`.
The latter will set the `a` field of the input to the `a`
field's `b` field, producing `{"a": 10, "b": 20}`.
Example: .a = .b
Input: {"a": {"b": 10}, "b": 20}
Output: {"a":20,"b":20}
Example: .a |= .b
Input: {"a": {"b": 10}, "b": 20}
Output: {"a":10,"b":20}
Example: (.a, .b) = range(3)
Input: null
Output: {"a":0,"b":0}
{"a":1,"b":1}
{"a":2,"b":2}
Example: (.a, .b) |= range(3)
Input: null
Output: {"a":0,"b":0}
----------------------------------------------------------------------------
Complex assignments
----------------------------------------------------------------------------
Lots more things are allowed on the left-hand side of a jq assignment
than in most languages. We've already seen simple field accesses on
the left hand side, and it's no surprise that array accesses work just
as well:
.posts[0].title = "JQ Manual"
What may come as a surprise is that the expression on the left may
produce multiple results, referring to different points in the input
document:
.posts[].comments |= . + ["this is great"]
That example appends the string "this is great" to the "comments"
array of each post in the input (where the input is an object with a
field "posts" which is an array of posts).
When jq encounters an assignment like 'a = b', it records the "path"
taken to select a part of the input document while executing a. This
path is then used to find which part of the input to change while
executing the assignment. Any filter may be used on the
left-hand side of an equals - whichever paths it selects from the
input will be where the assignment is performed.
This is a very powerful operation. Suppose we wanted to add a comment
to blog posts, using the same "blog" input above. This time, we only
want to comment on the posts written by "stedolan". We can find those
posts using the "select" function described earlier:
.posts[] | select(.author == "stedolan")
The paths provided by this operation point to each of the posts that
"stedolan" wrote, and we can comment on each of them in the same way
that we did before:
(.posts[] | select(.author == "stedolan") | .comments) |=
. + ["terrible."]
============================================================================
SECTION: Comments
============================================================================
You can write comments in your jq filters using `#`.
A `#` character (not part of a string) starts a comment.
All characters from `#` to the end of the line are ignored.
If the end of the line is preceded by an odd number of backslash
characters, the following line is also considered part of the
comment and is ignored.
For example, the following code outputs `[1,3,4,7]`
[
1,
# foo \
2,
# bar \\
3,
4, # baz \\\
5, \
6,
7
# comment \
comment \
comment
]
Backslash continuing the comment on the next line can be useful
when writing the "shebang" for a jq script:
#!/bin/sh --
# total - Output the sum of the given arguments (or stdin)
# usage: total [numbers...]
# \
exec jq --args -MRnf -- "$0" "$@"
$ARGS.positional |
reduce (
if . == []
then inputs
else .[]
end |
. as $dot |
try tonumber catch false |
if not or isnan then
@json "total: Invalid number \($dot).\n" | halt_error(1)
end
) as $n (0; . + $n)
The `exec` line is considered a comment by jq, so it is ignored.
But it is not ignored by `sh`, since in `sh` a backslash at the
end of the line does not continue the comment.
With this trick, when the script is invoked as `total 1 2`,
`/bin/sh -- /path/to/total 1 2` will be run, and `sh` will then
run `exec jq --args -MRnf -- /path/to/total 1 2` replacing itself
with a `jq` interpreter invoked with the specified options (`-M`,
`-R`, `-n`, `--args`), that evaluates the current file (`$0`),
with the arguments (`$@`) that were passed to `sh`.
============================================================================
SECTION: Modules
============================================================================
jq has a library/module system. Modules are files whose names end
in `.jq`.
Modules imported by a program are searched for in a default search
path (see below). The `import` and `include` directives allow the
importer to alter this path.
Paths in the search path are subject to various substitutions.
For paths starting with `~/`, the user's home directory is
substituted for `~`.
For paths starting with `$ORIGIN/`, the directory where the jq
executable is located is substituted for `$ORIGIN`.
For paths starting with `./` or paths that are `.`, the path of
the including file is substituted for `.`. For top-level programs
given on the command-line, the current directory is used.
Import directives can optionally specify a search path to which
the default is appended.
The default search path is the search path given to the `-L`
command-line option, else `["~/.jq", "$ORIGIN/../lib/jq",
"$ORIGIN/../lib"]`.
Null and empty string path elements terminate search path
processing.
A dependency with relative path `foo/bar` would be searched for in
`foo/bar.jq` and `foo/bar/bar.jq` in the given search path. This
is intended to allow modules to be placed in a directory along
with, for example, version control files, README files, and so on,
but also to allow for single-file modules.
Consecutive components with the same name are not allowed to avoid
ambiguities (e.g., `foo/foo`).
For example, with `-L$HOME/.jq` a module `foo` can be found in
`$HOME/.jq/foo.jq` and `$HOME/.jq/foo/foo.jq`.
If `.jq` exists in the user's home directory, and is a file (not a
directory), it is automatically sourced into the main program.
----------------------------------------------------------------------------
`import RelativePathString as NAME [<metadata>];`
----------------------------------------------------------------------------
Imports a module found at the given path relative to a
directory in a search path. A `.jq` suffix will be added to
the relative path string. The module's symbols are prefixed
with `NAME::`.
The optional metadata must be a constant jq expression. It
should be an object with keys like `homepage` and so on. At
this time jq only uses the `search` key/value of the metadata.
The metadata is also made available to users via the
`modulemeta` builtin.
The `search` key in the metadata, if present, should have a
string or array value (array of strings); this is the search
path to be prefixed to the top-level search path.
----------------------------------------------------------------------------
`include RelativePathString [<metadata>];`
----------------------------------------------------------------------------
Imports a module found at the given path relative to a
directory in a search path as if it were included in place. A
`.jq` suffix will be added to the relative path string. The
module's symbols are imported into the caller's namespace as
if the module's content had been included directly.
The optional metadata must be a constant jq expression. It
should be an object with keys like `homepage` and so on. At
this time jq only uses the `search` key/value of the metadata.
The metadata is also made available to users via the
`modulemeta` builtin.
----------------------------------------------------------------------------
`import RelativePathString as $NAME [<metadata>];`
----------------------------------------------------------------------------
Imports a JSON file found at the given path relative to a
directory in a search path. A `.json` suffix will be added to
the relative path string. The file's data will be available
as `$NAME::NAME`.
The optional metadata must be a constant jq expression. It
should be an object with keys like `homepage` and so on. At
this time jq only uses the `search` key/value of the metadata.
The metadata is also made available to users via the
`modulemeta` builtin.
The `search` key in the metadata, if present, should have a
string or array value (array of strings); this is the search
path to be prefixed to the top-level search path.
----------------------------------------------------------------------------
`module <metadata>;`
----------------------------------------------------------------------------
This directive is entirely optional. It's not required for
proper operation. It serves only the purpose of providing
metadata that can be read with the `modulemeta` builtin.
The metadata must be a constant jq expression. It should be
an object with keys like `homepage`. At this time jq doesn't
use this metadata, but it is made available to users via the
`modulemeta` builtin.
----------------------------------------------------------------------------
`modulemeta`
----------------------------------------------------------------------------
Takes a module name as input and outputs the module's metadata
as an object, with the module's imports (including metadata)
as an array value for the `deps` key and the module's defined
functions as an array value for the `defs` key.
Programs can use this to query a module's metadata, which they
could then use to, for example, search for, download, and
install missing dependencies.</pblock>
<pblock filename="jq.test" role="context" path="/mnt/c/Users/barlo/projects/drydock/uat/jq/runs/20260822.044627/workspace/targets/jq/blueprint/jq.test">
# Tests are groups of three lines: program, input, expected output
# Blank lines and lines starting with # are ignored
#
# Simple value tests to check parser. Input is irrelevant
#
true
null
true
false
null
false
null
42
null
1
null
1
-1
null
-1
# FIXME: much more number testing needed
{}
null
{}
[]
null
[]
{x:-1},{x:-.},{x:-.|abs}
1
{"x":-1}
{"x":-1}
{"x":1}
# The input line starts with a 0xFEFF (byte order mark) codepoint
# No, there is no reason to have a byte order mark in UTF8 text.
# But apparently people do, so jq shouldn't break on it.
.
"byte order mark"
"byte order mark"
# We test escapes by matching them against Unicode codepoints
# FIXME: more tests needed for weird unicode stuff (e.g. utf16 pairs)
"Aa\r\n\t\b\f\u03bc"
null
"Aa\u000d\u000a\u0009\u0008\u000c\u03bc"
.
"Aa\r\n\t\b\f\u03bc"
"Aa\u000d\u000a\u0009\u0008\u000c\u03bc"
%%FAIL
"u\vw"
jq: error: Invalid escape at line 1, column 4 (while parsing '"\v"') at <top-level>, line 1, column 3:
"u\vw"
^^
"inter\("pol" + "ation")"
null
"interpolation"
@text,@json,([1,.]|@csv,@tsv),@html,(@uri|.,@urid),@sh,(@base64|.,@base64d)
"!()<>&'\"\t"
"!()<>&'\"\t"
"\"!()<>&'\\\"\\t\""
"1,\"!()<>&'\"\"\t\""
"1\t!()<>&'\"\\t"
"!()<>&'"\t"
"%21%28%29%3C%3E%26%27%22%09"
"!()<>&'\"\t"
"'!()<>&'\\''\"\t'"
"ISgpPD4mJyIJ"
"!()<>&'\"\t"
# regression test for #436
@base64
"foóbar\n"
"Zm/Ds2Jhcgo="
@base64d
"Zm/Ds2Jhcgo="
"foóbar\n"
@uri
"\u03bc"
"%CE%BC"
@urid
"%CE%BC"
"\u03bc"
@html "<b>\(.)</b>"
"<script>hax</script>"
"<b><script>hax</script></b>"
[.[]|tojson|fromjson]
["foo", 1, ["a", 1, "b", 2, {"foo":"bar"}]]
["foo",1,["a",1,"b",2,{"foo":"bar"}]]
#
# Dictionary construction syntax
#
{a: 1}
null
{"a":1}
{a,b,(.d):.a,e:.b}
{"a":1, "b":2, "c":3, "d":"c"}
{"a":1, "b":2, "c":1, "e":2}
{"a",b,"a$\(1+1)"}
{"a":1, "b":2, "c":3, "a$2":4}
{"a":1, "b":2, "a$2":4}
%%FAIL
{(0):1}
jq: error: Cannot use number (0) as object key at <top-level>, line 1, column 3:
{(0):1}
^
%%FAIL
{1+2:3}
jq: error: May need parentheses around object key expression at <top-level>, line 1, column 2:
{1+2:3}
^^^
%%FAIL
{non_const:., (0):1}
jq: error: Cannot use number (0) as object key at <top-level>, line 1, column 16:
{non_const:., (0):1}
^
#
# Field access, piping
#
.foo
{"foo": 42, "bar": 43}
42
.foo | .bar
{"foo": {"bar": 42}, "bar": "badvalue"}
42
.foo.bar
{"foo": {"bar": 42}, "bar": "badvalue"}
42
.foo_bar
{"foo_bar": 2}
2
.["foo"].bar
{"foo": {"bar": 42}, "bar": "badvalue"}
42
."foo"."bar"
{"foo": {"bar": 20}}
20
.e0, .E1, .E-1, .E+1
{"e0": 1, "E1": 2, "E": 3}
1
2
2
4
[.[]|.foo?]
[1,[2],{"foo":3,"bar":4},{},{"foo":5}]
[3,null,5]
[.[]|.foo?.bar?]
[1,[2],[],{"foo":3},{"foo":{"bar":4}},{}]
[4,null]
[..]
[1,[[2]],{ "a":[1]}]
[[1,[[2]],{"a":[1]}],1,[[2]],[2],2,{"a":[1]},[1],1]
[.[]|.[]?]
[1,null,[],[1,[2,[[3]]]],[{}],[{"a":[1,[2]]}]]
[1,[2,[[3]]],{},{"a":[1,[2]]}]
[.[]|.[1:3]?]
[1,null,true,false,"abcdef",{},{"a":1,"b":2},[],[1,2,3,4,5],[1,2]]
[null,"bc",[],[2,3],[2]]
# chaining/suffix-list, with and without dot
map(try .a[] catch ., try .a.[] catch ., .a[]?, .a.[]?)
[{"a": [1,2]}, {"a": 123}]
[1,2,1,2,1,2,1,2,"Cannot iterate over number (123)","Cannot iterate over number (123)"]
# oss-fuzz #66070: objects[] leaks if a non-last element throws an error
try ["OK", (.[] | error)] catch ["KO", .]
{"a":["b"],"c":["d"]}
["KO",["b"]]
#
# Negative array indices
#
try (.foo[-1] = 0) catch .
null
"Out of bounds negative array index"
try (.foo[-2] = 0) catch .
null
"Out of bounds negative array index"
.[-1] = 5
[0,1,2]
[0,1,5]
.[-2] = 5
[0,1,2]
[0,5,2]
try (.[999999999] = 0) catch .
null
"Array index too large"
#
# Multiple outputs, iteration
#
.[]
[1,2,3]
1
2
3
1,1
[]
1
1
1,.
[]
1
[]
[.]
[2]
[[2]]
[[2]]
[3]
[[2]]
[{}]
[2]
[{}]
[.[]]
["a"]
["a"]
[(.,1),((.,.[]),(2,3))]
["a","b"]
[["a","b"],1,["a","b"],"a","b",2,3]
[([5,5][]),.,.[]]
[1,2,3]
[5,5,[1,2,3],1,2,3]
{x: (1,2)},{x:3} | .x
null
1
2
3
[.[-4,-3,-2,-1,0,1,2,3]]
[1,2,3]
[null,1,2,3,1,2,3,null]
[range(0;10)]
null
[0,1,2,3,4,5,6,7,8,9]
[range(0,1;3,4)]
null
[0,1,2, 0,1,2,3, 1,2, 1,2,3]
[range(0;10;3)]
null
[0,3,6,9]
[range(0;10;-1)]
null
[]
[range(0;-5;-1)]
null
[0,-1,-2,-3,-4]
[range(0,1;4,5;1,2)]
null
[0,1,2,3,0,2, 0,1,2,3,4,0,2,4, 1,2,3,1,3, 1,2,3,4,1,3]
[while(.<100; .*2)]
1
[1,2,4,8,16,32,64]
[(label $here | .[] | if .>1 then break $here else . end), "hi!"]
[0,1,2]
[0,1,"hi!"]
[(label $here | .[] | if .>1 then break $here else . end), "hi!"]
[0,2,1]
[0,"hi!"]
%%FAIL
. as $foo | break $foo
jq: error: $*label-foo is not defined at <top-level>, line 1, column 13:
. as $foo | break $foo
^^^^^^^^^^
[.[]|[.,1]|until(.[0] < 1; [.[0] - 1, .[1] * .[0]])|.[1]]
[1,2,3,4,5]
[1,2,6,24,120]
[label $out | foreach .[] as $item ([3, null]; if .[0] < 1 then break $out else [.[0] -1, $item] end; .[1])]
[11,22,33,44,55,66,77,88,99]
[11,22,33]
[foreach range(5) as $item (0; $item)]
null
[0,1,2,3,4]
[foreach .[] as [$i, $j] (0; . + $i - $j)]
[[2,1], [5,3], [6,4]]
[1,3,5]
[foreach .[] as {a:$a} (0; . + $a; -.)]
[{"a":1}, {"b":2}, {"a":3, "b":4}]
[-1, -1, -4]
[-foreach -.[] as $x (0; . + $x)]
[1,2,3]
[1,3,6]
[foreach .[] / .[] as $i (0; . + $i)]
[1,2]
[1,3,3.5,4.5]
[foreach .[] as $x (0; . + $x) as $x | $x]
[1,2,3]
[1,3,6]
[limit(3; .[])]
[11,22,33,44,55,66,77,88,99]
[11,22,33]
[limit(0; error)]
"badness"
[]
[limit(1; 1, error)]
"badness"
[1]
try limit(-1; error) catch .
null
"limit doesn't support negative count"
[skip(3; .[])]
[1,2,3,4,5,6,7,8,9]
[4,5,6,7,8,9]
[skip(0,2,3,4; .[])]
[1,2,3]
[1,2,3,3]
[skip(3; .[])]
[]
[]
try skip(-1; error) catch .
null
"skip doesn't support negative count"
nth(1; 0,1,error("foo"))
null
1
[first(range(.)), last(range(.))]
10
[0,9]
[first(range(.)), last(range(.))]
0
[]
[nth(0,5,9,10,15; range(.)), try nth(-1; range(.)) catch .]
10
[0,5,9,"nth doesn't support negative indices"]
# Check that first(g) does not extract more than one value from g
first(1,error("foo"))
null
1
#
# Check that various builtins evaluate all arguments where appropriate,
# doing cartesian products where appropriate.
#
# Check that limit does work for each value produced by n!
[limit(5,7; range(9))]
null
[0,1,2,3,4,0,1,2,3,4,5,6]
# Same check for nth
[nth(5,7; range(9;0;-1))]
null
[4,2]
# Same check for range/3
[range(0,1,2;4,3,2;2,3)]
null
[0,2,0,3,0,2,0,0,0,1,3,1,1,1,1,1,2,2,2,2]
# Same check for range/1
[range(3,5)]
null
[0,1,2,0,1,2,3,4]
# Same check for index/1, rindex/1, indices/1
[(index(",","|"), rindex(",","|")), indices(",","|")]
"a,b|c,d,e||f,g,h,|,|,i,j"
[1,3,22,19,[1,5,7,12,14,16,18,20,22],[3,9,10,17,19]]
# Same check for join/1
join(",","/")
["a","b","c","d"]
"a,b,c,d"
"a/b/c/d"
[.[]|join("a")]
[[],[""],["",""],["","",""]]
["","","a","aa"]
# Same check for flatten/1
flatten(3,2,1)
[0, [1], [[2]], [[[3]]]]
[0,1,2,3]
[0,1,2,[3]]
[0,1,[2],[[3]]]
#
# Slices
#
[.[3:2], .[-5:4], .[:-2], .[-2:], .[3:3][1:], .[10:]]
[0,1,2,3,4,5,6]
[[], [2,3], [0,1,2,3,4], [5,6], [], []]
[.[3:2], .[-5:4], .[:-2], .[-2:], .[3:3][1:], .[10:]]
"abcdefghi"
["","","abcdefg","hi","",""]
del(.[2:4],.[0],.[-2:])
[0,1,2,3,4,5,6,7]
[1,4,5]
.[2:4] = ([], ["a","b"], ["a","b","c"])
[0,1,2,3,4,5,6,7]
[0,1,4,5,6,7]
[0,1,"a","b",4,5,6,7]
[0,1,"a","b","c",4,5,6,7]
# Slices at large offsets (issue #1108)
#
# This is written this way because [range(<large number>)] is
# significantly slower under valgrind than .[<large number>] = value.
#
# We range down rather than up so that we have just one realloc.
reduce range(65540;65536;-1) as $i ([]; .[$i] = $i)|.[65536:]
null
[null,65537,65538,65539,65540]
#
# Variables
#
1 as $x | 2 as $y | [$x,$y,$x]
null
[1,2,1]
[1,2,3][] as $x | [[4,5,6,7][$x]]
null
[5]
[6]
[7]
42 as $x | . | . | . + 432 | $x + 1
34324
43
1 + 2 as $x | -$x
null
-3
"x" as $x | "a"+"y" as $y | $x+","+$y
null
"x,ay"
1 as $x | [$x,$x,$x as $x | $x]
null
[1,1,1]
[1, {c:3, d:4}] as [$a, {c:$b, b:$c}] | $a, $b, $c
null
1
3
null
. as {as: $kw, "str": $str, ("e"+"x"+"p"): $exp} | [$kw, $str, $exp]
{"as": 1, "str": 2, "exp": 3}
[1, 2, 3]
.[] as [$a, $b] | [$b, $a]
[[1], [1, 2, 3]]
[null, 1]
[2, 1]
. as $i | . as [$i] | $i
[0]
0
. as [$i] | . as $i | $i
[0]
[0]
%%FAIL
. as [] | null
jq: error: syntax error, unexpected ']', expecting BINDING or '[' or '{' at <top-level>, line 1, column 7:
. as [] | null
^
%%FAIL
. as {} | null
jq: error: syntax error, unexpected '}' at <top-level>, line 1, column 7:
. as {} | null
^
%%FAIL
. as $foo | [$foo, $bar]
jq: error: $bar is not defined at <top-level>, line 1, column 20:
. as $foo | [$foo, $bar]
^^^^
%%FAIL
. as {(true):$foo} | $foo
jq: error: Cannot use boolean (true) as object key at <top-level>, line 1, column 8:
. as {(true):$foo} | $foo
^^^^
# [.,(.[] | {x:.},.),.,.[]]
#
# Builtin functions
#
1+1
null
2
1+1
"wtasdf"
2.0
2-1
null
1
2-(-1)
null
3
1e+0+0.001e3
"I wonder what this will be?"
20e-1
.+4
15
19.0
.+null
{"a":42}
{"a":42}
null+.
null
null
.a+.b
{"a":42}
42
[1,2,3] + [.]
null
[1,2,3,null]
{"a":1} + {"b":2} + {"c":3}
"asdfasdf"
{"a":1, "b":2, "c":3}
"asdf" + "jkl;" + . + . + .
"some string"
"asdfjkl;some stringsome stringsome string"
"\u0000\u0020\u0000" + .
"\u0000\u0020\u0000"
"\u0000 \u0000\u0000 \u0000"
42 - .
11
31
[1,2,3,4,1] - [.,3]
1
[2,4]
[-1 as $x | 1,$x]
null
[1,-1]
[10 * 20, 20 / .]
4
[200, 5]
1 + 2 * 2 + 10 / 2
null
10
[16 / 4 / 2, 16 / 4 * 2, 16 - 4 - 2, 16 - 4 + 2]
null
[2, 8, 10, 14]
1e-19 + 1e-20 - 5e-21
null
1.05e-19
1 / 1e-17
null
1e+17
9E999999999, 9999999999E999999990, 1E-999999999, 0.000000001E-999999990
null
9E+999999999
9.999999999E+999999999
1E-999999999
1E-999999999
5E500000000 > 5E-5000000000, 10000E500000000 > 10000E-5000000000
null
true
true
# #2825
(1e999999999, 10e999999999) > (1e-1147483646, 0.1e-1147483646)
null
true
true
true
true
25 % 7
null
4
49732 % 472
null
172
[(infinite, -infinite) % (1, -1, infinite)]
null
[0,0,0,0,0,-1]
[nan % 1, 1 % nan | isnan]
null
[true,true]
1 + tonumber + ("10" | tonumber)
4
15
"123\u0000456" | try tonumber catch .
null
"string (\"123\\u0000456\") cannot be parsed as a number"
map(toboolean)
["false","true",false,true]
[false,true,false,true]
.[] | try toboolean catch .
[null,0,"tru","truee","fals","falsee",[],{}]
"null (null) cannot be parsed as a boolean"
"number (0) cannot be parsed as a boolean"
"string (\"tru\") cannot be parsed as a boolean"
"string (\"truee\") cannot be parsed as a boolean"
"string (\"fals\") cannot be parsed as a boolean"
"string (\"falsee\") cannot be parsed as a boolean"
"array ([]) cannot be parsed as a boolean"
"object ({}) cannot be parsed as a boolean"
"true\u0000x", "false\u0000" | try toboolean catch .
null
"string (\"true\\u0000x\") cannot be parsed as a boolean"
"string (\"false\\u0000\") cannot be parsed as a boolean"
[{"a":42},.object,10,.num,false,true,null,"b",[1,4]] | .[] as $x | [$x == .[]]
{"object": {"a":42}, "num":10.0}
[true, true, false, false, false, false, false, false, false]
[true, true, false, false, false, false, false, false, false]
[false, false, true, true, false, false, false, false, false]
[false, false, true, true, false, false, false, false, false]
[false, false, false, false, true, false, false, false, false]
[false, false, false, false, false, true, false, false, false]
[false, false, false, false, false, false, true, false, false]
[false, false, false, false, false, false, false, true, false]
[false, false, false, false, false, false, false, false, true ]
[.[] | length]
[[], {}, [1,2], {"a":42}, "asdf", "\u03bc"]
[0, 0, 2, 1, 4, 1]
utf8bytelength
"asdf\u03bc"
6
[.[] | try utf8bytelength catch .]
[[], {}, [1,2], 55, true, false]
["array ([]) only strings have UTF-8 byte length","object ({}) only strings have UTF-8 byte length","array ([1,2]) only strings have UTF-8 byte length","number (55) only strings have UTF-8 byte length","boolean (true) only strings have UTF-8 byte length","boolean (false) only strings have UTF-8 byte length"]
map(keys)
[{}, {"abcd":1,"abc":2,"abcde":3}, {"x":1, "z": 3, "y":2}]
[[], ["abc","abcd","abcde"], ["x","y","z"]]
[1,2,empty,3,empty,4]
null
[1,2,3,4]
map(add)
[[], [1,2,3], ["a","b","c"], [[3],[4,5],[6]], [{"a":1}, {"b":2}, {"a":3}]]
[null, 6, "abc", [3,4,5,6], {"a":3, "b": 2}]
map_values(.+1)
[0,1,2]
[1,2,3]
[add(null), add(range(range(10))), add(empty), add(10,range(10))]
null
[null,120,null,55]
# Real-world use case for add(empty)
.sum = add(.arr[])
{"arr":[]}
{"arr":[],"sum":null}
add({(.[]):1}) | keys
["a","a","b","a","d","b","d","a","d"]
["a","b","d"]
#
# User-defined functions
# Oh god.
#
def f: . + 1; def g: def g: . + 100; f | g | f; (f | g), g
3.0
106.0
105.0
def f: (1000,2000); f
123412345
1000
2000
def f(a;b;c;d;e;f): [a+1,b,c,d,e,f]; f(.[0];.[1];.[0];.[0];.[0];.[0])
[1,2]
[2,2,1,1,1,1]
def f: 1; def g: f, def f: 2; def g: 3; f, def f: g; f, g; def f: 4; [f, def f: g; def g: 5; f, g]+[f,g]
null
[4,1,2,3,3,5,4,1,2,3,3]
# Test precedence of 'def' vs '|'
def a: 0; . | a
null
0
# Many arguments
def f(a;b;c;d;e;f;g;h;i;j): [j,i,h,g,f,e,d,c,b,a]; f(.[0];.[1];.[2];.[3];.[4];.[5];.[6];.[7];.[8];.[9])
[0,1,2,3,4,5,6,7,8,9]
[9,8,7,6,5,4,3,2,1,0]
([1,2] + [4,5])
[1,2,3]
[1,2,4,5]
true
[1]
true
null,1,null
"hello"
null
1
null
[1,2,3]
[5,6]
[1,2,3]
[.[]|floor]
[-1.1,1.1,1.9]
[-2, 1, 1]
[.[]|sqrt]
[4,9]
[2,3]
(add / length) as $m | map((. - $m) as $d | $d * $d) | add / length | sqrt
[2,4,4,4,5,5,7,9]
2
# Should write a test that calls the -lm function from C (or bc(1)) to
# check that they match the corresponding jq functions. However,
# there's so little template code standing between that it suffices to
# test a handful of these. The results were checked by eye against
# bc(1).
atan * 4 * 1000000|floor / 1000000
1
3.141592
[(3.141592 / 2) * (range(0;20) / 20)|cos * 1000000|floor / 1000000]
null
[1,0.996917,0.987688,0.972369,0.951056,0.923879,0.891006,0.85264,0.809017,0.760406,0.707106,0.649448,0.587785,0.522498,0.45399,0.382683,0.309017,0.233445,0.156434,0.078459]
[(3.141592 / 2) * (range(0;20) / 20)|sin * 1000000|floor / 1000000]
null
[0,0.078459,0.156434,0.233445,0.309016,0.382683,0.45399,0.522498,0.587785,0.649447,0.707106,0.760405,0.809016,0.85264,0.891006,0.923879,0.951056,0.972369,0.987688,0.996917]
def f(x): x | x; f([.], . + [42])
[1,2,3]
[[[1,2,3]]]
[[1,2,3],42]
[[1,2,3,42]]
[1,2,3,42,42]
# test multiple function arities and redefinition
def f: .+1; def g: f; def f: .+100; def f(a):a+.+11; [(g|f(20)), f]
1
[33,101]
# test closures and lexical scoping
def id(x):x; 2000 as $x | def f(x):1 as $x | id([$x, x, x]); def g(x): 100 as $x | f($x,$x+x); g($x)
"more testing"
[1,100,2100.0,100,2100.0]
# test def f($a) syntax
def x(a;b): a as $a | b as $b | $a + $b; def y($a;$b): $a + $b; def check(a;b): [x(a;b)] == [y(a;b)]; check(.[];.[]*2)
[1,2,3]
true
# test backtracking through function calls and returns
# this test is *evil*
[[20,10][1,0] as $x | def f: (100,200) as $y | def g: [$x + $y, .]; . + $x | g; f[0] | [f][0][1] | f]
999999999
[[110.0, 130.0], [210.0, 130.0], [110.0, 230.0], [210.0, 230.0], [120.0, 160.0], [220.0, 160.0], [120.0, 260.0], [220.0, 260.0]]
# test recursion
def fac: if . == 1 then 1 else . * (. - 1 | fac) end; [.[] | fac]
[1,2,3,4]
[1,2,6,24]
# test stack overflow and reallocation
# this test is disabled for now, it takes a realllllly long time.
# def f: if length > 1000 then . else .+[1]|f end; f | length
# []
# 1001
reduce .[] as $x (0; . + $x)
[1,2,4]
7
reduce .[] as [$i, {j:$j}] (0; . + $i - $j)
[[2,{"j":1}], [5,{"j":3}], [6,{"j":4}]]
5
reduce [[1,2,10], [3,4,10]][] as [$i,$j] (0; . + $i * $j)
null
14
[-reduce -.[] as $x (0; . + $x)]
[1,2,3]
[6]
[reduce .[] / .[] as $i (0; . + $i)]
[1,2]
[4.5]
reduce .[] as $x (0; . + $x) as $x | $x
[1,2,3]
6
# This, while useless, should still compile.
reduce . as $n (.; .)
null
null
# Destructuring
. as {$a, b: [$c, {$d}]} | [$a, $c, $d]
{"a":1, "b":[2,{"d":3}]}
[1,2,3]
. as {$a, $b:[$c, $d]}| [$a, $b, $c, $d]
{"a":1, "b":[2,{"d":3}]}
[1,[2,{"d":3}],2,{"d":3}]
# Destructuring with alternation
.[] | . as {$a, b: [$c, {$d}]} ?// [$a, {$b}, $e] ?// $f | [$a, $b, $c, $d, $e, $f]
[{"a":1, "b":[2,{"d":3}]}, [4, {"b":5, "c":6}, 7, 8, 9], "foo"]
[1, null, 2, 3, null, null]
[4, 5, null, null, 7, null]
[null, null, null, null, null, "foo"]
# Destructuring DUP/POP issues
.[] | . as {a:$a} ?// {a:$a} ?// {a:$a} | $a
[[3],[4],[5],6]
# Runtime error: "jq: Cannot index array with string (\"c\")"
.[] as {a:$a} ?// {a:$a} ?// {a:$a} | $a
[[3],[4],[5],6]
# Runtime error: "jq: Cannot index array with string (\"c\")"
[[3],[4],[5],6][] | . as {a:$a} ?// {a:$a} ?// {a:$a} | $a
null
# Runtime error: "jq: Cannot index array with string (\"c\")"
[[3],[4],[5],6] | .[] as {a:$a} ?// {a:$a} ?// {a:$a} | $a
null
# Runtime error: "jq: Cannot index array with string (\"c\")"
.[] | . as {a:$a} ?// {a:$a} ?// $a | $a
[[3],[4],[5],6]
[3]
[4]
[5]
6
.[] as {a:$a} ?// {a:$a} ?// $a | $a
[[3],[4],[5],6]
[3]
[4]
[5]
6
[[3],[4],[5],6][] | . as {a:$a} ?// {a:$a} ?// $a | $a
null
[3]
[4]
[5]
6
[[3],[4],[5],6] | .[] as {a:$a} ?// {a:$a} ?// $a | $a
null
[3]
[4]
[5]
6
.[] | . as {a:$a} ?// $a ?// {a:$a} | $a
[[3],[4],[5],6]
[3]
[4]
[5]
6
.[] as {a:$a} ?// $a ?// {a:$a} | $a
[[3],[4],[5],6]
[3]
[4]
[5]
6
[[3],[4],[5],6][] | . as {a:$a} ?// $a ?// {a:$a} | $a
null
[3]
[4]
[5]
6
[[3],[4],[5],6] | .[] as {a:$a} ?// $a ?// {a:$a} | $a
null
[3]
[4]
[5]
6
.[] | . as $a ?// {a:$a} ?// {a:$a} | $a
[[3],[4],[5],6]
[3]
[4]
[5]
6
.[] as $a ?// {a:$a} ?// {a:$a} | $a
[[3],[4],[5],6]
[3]
[4]
[5]
6
[[3],[4],[5],6][] | . as $a ?// {a:$a} ?// {a:$a} | $a
null
[3]
[4]
[5]
6
[[3],[4],[5],6] | .[] as $a ?// {a:$a} ?// {a:$a} | $a
null
[3]
[4]
[5]
6
. as $dot|any($dot[];not)
[1,2,3,4,true,false,1,2,3,4,5]
true
. as $dot|any($dot[];not)
[1,2,3,4,true]
false
. as $dot|all($dot[];.)
[1,2,3,4,true,false,1,2,3,4,5]
false
. as $dot|all($dot[];.)
[1,2,3,4,true]
true
# Check short-circuiting
any(true, error; .)
"badness"
true
all(false, error; .)
"badness"
false
any(not)
[]
false
all(not)
[]
true
any(not)
[false]
true
all(not)
[false]
true
[any,all]
[]
[false,true]
[any,all]
[true]
[true,true]
[any,all]
[false]
[false,false]
[any,all]
[true,false]
[true,false]
[any,all]
[null,null,true]
[true,false]
#
# Paths
#
path(.foo[0,1])
null
["foo", 0]
["foo", 1]
path(.[] | select(.>3))
[1,5,3]
[1]
path(.)
42
[]
try path(.a | map(select(.b == 0))) catch .
{"a":[{"b":0}]}
"Invalid path expression with result [{\"b\":0}]"
try path(.a | map(select(.b == 0)) | .[0]) catch .
{"a":[{"b":0}]}
"Invalid path expression near attempt to access element 0 of [{\"b\":0}]"
try path(.a | map(select(.b == 0)) | .c) catch .
{"a":[{"b":0}]}
"Invalid path expression near attempt to access element \"c\" of [{\"b\":0}]"
try path(.a | map(select(.b == 0)) | .[]) catch .
{"a":[{"b":0}]}
"Invalid path expression near attempt to iterate through [{\"b\":0}]"
path(.a[path(.b)[0]])
{"a":{"b":0}}
["a","b"]
[paths]
[1,[[],{"a":2}]]
[[0],[1],[1,0],[1,1],[1,1,"a"]]
["foo",1] as $p | getpath($p), setpath($p; 20), delpaths([$p])
{"bar": 42, "foo": ["a", "b", "c", "d"]}
"b"
{"bar": 42, "foo": ["a", 20, "c", "d"]}
{"bar": 42, "foo": ["a", "c", "d"]}
map(getpath([2])), map(setpath([2]; 42)), map(delpaths([[2]]))
[[0], [0,1], [0,1,2]]
[null, null, 2]
[[0,null,42], [0,1,42], [0,1,42]]
[[0], [0,1], [0,1]]
map(delpaths([[0,"foo"]]))
[[{"foo":2, "x":1}], [{"bar":2}]]
[[{"x":1}], [{"bar":2}]]
["foo",1] as $p | getpath($p), setpath($p; 20), delpaths([$p])
{"bar":false}
null
{"bar":false, "foo": [null, 20]}
{"bar":false}
delpaths([[-200]])
[1,2,3]
[1,2,3]
try delpaths(0) catch .
{}
"Paths must be specified as an array"
del(.), del(empty), del((.foo,.bar,.baz) | .[2,3,0]), del(.foo[0], .bar[0], .foo, .baz.bar[0].x)
{"foo": [0,1,2,3,4], "bar": [0,1]}
null
{"foo": [0,1,2,3,4], "bar": [0,1]}
{"foo": [1,4], "bar": [1]}
{"bar": [1]}
del(.[1], .[-6], .[2], .[-3:9])
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
[0, 3, 5, 6, 9]
del(.[nan])
[1,2,3]
[1,2,3]
del(.[nan,nan])
[1,2,3]
[1,2,3]
# negative index
setpath([-1]; 1)
[0]
[1]
pick(.a.b.c)
null
{"a":{"b":{"c":null}}}
pick(first)
[1,2]
[1]
pick(first|first)
[[10,20],30]
[[10]]
# negative indices in path expressions (since last/1 is .[-1])
try pick(last) catch .
[1,2]
"Out of bounds negative array index"
#
# Assignment
#
.message = "goodbye"
{"message": "hello"}
{"message": "goodbye"}
.foo = .bar
{"bar":42}
{"foo":42, "bar":42}
.foo |= .+1
{"foo": 42}
{"foo": 43}
.[] += 2, .[] *= 2, .[] -= 2, .[] /= 2, .[] %=2
[1,3,5]
[3,5,7]
[2,6,10]
[-1,1,3]
[0.5, 1.5, 2.5]
[1,1,1]
[.[] % 7]
[-7,-6,-5,-4,-3,-2,-1,0,1,2,3,4,5,6,7]
[0,-6,-5,-4,-3,-2,-1,0,1,2,3,4,5,6,0]
.foo += .foo
{"foo":2}
{"foo":4}
.[0].a |= {"old":., "new":(.+1)}
[{"a":1,"b":2}]
[{"a":{"old":1, "new":2},"b":2}]
def inc(x): x |= .+1; inc(.[].a)
[{"a":1,"b":2},{"a":2,"b":4},{"a":7,"b":8}]
[{"a":2,"b":2},{"a":3,"b":4},{"a":8,"b":8}]
# #1358, getpath/1 should work in path expressions
.[] | try (getpath(["a",0,"b"]) |= 5) catch .
[null,{"b":0},{"a":0},{"a":null},{"a":[0,1]},{"a":{"b":1}},{"a":[{}]},{"a":[{"c":3}]}]
{"a":[{"b":5}]}
{"b":0,"a":[{"b":5}]}
"Cannot index number with number (0)"
{"a":[{"b":5}]}
"Cannot index number with string (\"b\")"
"Cannot index object with number (0)"
{"a":[{"b":5}]}
{"a":[{"c":3,"b":5}]}
# #2051, deletion using assigning empty against arrays
(.[] | select(. >= 2)) |= empty
[1,5,3,0,7]
[1,0]
.[] |= select(. % 2 == 0)
[0,1,2,3,4,5]
[0,2,4]
.foo[1,4,2,3] |= empty
{"foo":[0,1,2,3,4,5]}
{"foo":[0,5]}
.[2][3] = 1
[4]
[4, null, [null, null, null, 1]]
.foo[2].bar = 1
{"foo":[11], "bar":42}
{"foo":[11,null,{"bar":1}], "bar":42}
try ((map(select(.a == 1))[].b) = 10) catch .
[{"a":0},{"a":1}]
"Invalid path expression near attempt to iterate through [{\"a\":1}]"
try ((map(select(.a == 1))[].a) |= .+1) catch .
[{"a":0},{"a":1}]
"Invalid path expression near attempt to iterate through [{\"a\":1}]"
def x: .[1,2]; x=10
[0,1,2]
[0,10,10]
try (def x: reverse; x=10) catch .
[0,1,2]
"Invalid path expression with result [2,1,0]"
.[] = 1
[1,null,Infinity,-Infinity,NaN,-NaN]
[1,1,1,1,1,1]
#
# Conditionals
#
[.[] | if .foo then "yep" else "nope" end]
[{"foo":0},{"foo":1},{"foo":[]},{"foo":true},{"foo":false},{"foo":null},{"foo":"foo"},{}]
["yep","yep","yep","yep","nope","nope","yep","nope"]
[.[] | if .baz then "strange" elif .foo then "yep" else "nope" end]
[{"foo":0},{"foo":1},{"foo":[]},{"foo":true},{"foo":false},{"foo":null},{"foo":"foo"},{}]
["yep","yep","yep","yep","nope","nope","yep","nope"]
[if 1,null,2 then 3 else 4 end]
null
[3,4,3]
[if empty then 3 else 4 end]
null
[]
[if 1 then 3,4 else 5 end]
null
[3,4]
[if null then 3 else 5,6 end]
null
[5,6]
[if true then 3 end]
7
[3]
[if false then 3 end]
7
[7]
[if false then 3 else . end]
7
[7]
[if false then 3 elif false then 4 end]
7
[7]
[if false then 3 elif false then 4 else . end]
7
[7]
[-if true then 1 else 2 end]
null
[-1]
{x: if true then 1 else 2 end}
null
{"x":1}
if true then [.] else . end []
null
null
[.[] | [.foo[] // .bar]]
[{"foo":[1,2], "bar": 42}, {"foo":[1], "bar": null}, {"foo":[null,false,3], "bar": 18}, {"foo":[], "bar":42}, {"foo": [null,false,null], "bar": 41}]
[[1,2], [1], [3], [42], [41]]
.[] //= .[0]
["hello",true,false,[false],null]
["hello",true,"hello",[false],"hello"]
.[] | [.[0] and .[1], .[0] or .[1]]
[[true,[]], [false,1], [42,null], [null,false]]
[true,true]
[false,true]
[false,true]
[false,false]
[.[] | not]
[1,0,false,null,true,"hello"]
[false,false,true,true,false,false]
# Check numeric comparison binops
[10 > 0, 10 > 10, 10 > 20, 10 < 0, 10 < 10, 10 < 20]
{}
[true,false,false,false,false,true]
[10 >= 0, 10 >= 10, 10 >= 20, 10 <= 0, 10 <= 10, 10 <= 20]
{}
[true,true,false,false,true,true]
# And some in/equality tests
[ 10 == 10, 10 != 10, 10 != 11, 10 == 11]
{}
[true,false,true,false]
["hello" == "hello", "hello" != "hello", "hello" == "world", "hello" != "world" ]
{}
[true,false,false,true]
[[1,2,3] == [1,2,3], [1,2,3] != [1,2,3], [1,2,3] == [4,5,6], [1,2,3] != [4,5,6]]
{}
[true,false,false,true]
[{"foo":42} == {"foo":42},{"foo":42} != {"foo":42}, {"foo":42} != {"bar":42}, {"foo":42} == {"bar":42}]
{}
[true,false,true,false]
# ugly complicated thing
[{"foo":[1,2,{"bar":18},"world"]} == {"foo":[1,2,{"bar":18},"world"]},{"foo":[1,2,{"bar":18},"world"]} == {"foo":[1,2,{"bar":19},"world"]}]
{}
[true,false]
# containment operator
[("foo" | contains("foo")), ("foobar" | contains("foo")), ("foo" | contains("foobar"))]
{}
[true, true, false]
# containment operator (embedded NULs!)
[contains(""), contains("\u0000")]
"\u0000"
[true, true]
[contains(""), contains("a"), contains("ab"), contains("c"), contains("d")]
"ab\u0000cd"
[true, true, true, true, true]
[contains("cd"), contains("b\u0000"), contains("ab\u0000")]
"ab\u0000cd"
[true, true, true]
[contains("b\u0000c"), contains("b\u0000cd"), contains("b\u0000cd")]
"ab\u0000cd"
[true, true, true]
[contains("@"), contains("\u0000@"), contains("\u0000what")]
"ab\u0000cd"
[false, false, false]
# Try/catch and general `?` operator
[.[]|try if . == 0 then error("foo") elif . == 1 then .a elif . == 2 then empty else . end catch .]
[0,1,2,3]
["foo","Cannot index number with string (\"a\")",3]
[.[]|(.a, .a)?]
[null,true,{"a":1}]
[null,null,1,1]
[[.[]|[.a,.a]]?]
[null,true,{"a":1}]
[]
[if error then 1 else 2 end?]
"foo"
[]
try error(0) // 1
null
1
1, try error(2), 3
null
1
3
1 + try 2 catch 3 + 4
null
7
[-try .]
1
[-1]
try -.? catch .
"foo"
"string (\"foo\") cannot be negated"
{x: try 1, y: try error catch 2, z: if true then 3 end}
null
{"x":1,"y":2,"z":3}
{x: 1 + 2, y: false or true, z: null // 3}
null
{"x":3,"y":true,"z":3}
.[] | try error catch .
[1,null,2]
1
null
2
try error("\($__loc__)") catch .
null
"{\"file\":\"<top-level>\",\"line\":1}"
# string operations
[.[]|startswith("foo")]
["fo", "foo", "barfoo", "foobar", "barfoob"]
[false, true, false, true, false]
[.[]|endswith("foo")]
["fo", "foo", "barfoo", "foobar", "barfoob"]
[false, true, true, false, false]
[.[] | split(", ")]
["a,b, c, d, e,f",", a,b, c, d, e,f, "]
[["a,b","c","d","e,f"],["","a,b","c","d","e,f",""]]
split("")
"abc"
["a","b","c"]
[.[]|ltrimstr("foo")]
["fo", "foo", "barfoo", "foobar", "afoo"]
["fo","","barfoo","bar","afoo"]
[.[]|rtrimstr("foo")]
["fo", "foo", "barfoo", "foobar", "foob"]
["fo","","bar","foobar","foob"]
[.[]|trimstr("foo")]
["fo", "foo", "barfoo", "foobarfoo", "foob"]
["fo","","bar","bar","b"]
[.[]|ltrimstr("")]
["a", "xx", ""]
["a", "xx", ""]
[.[]|rtrimstr("")]
["a", "xx", ""]
["a", "xx", ""]
[.[]|trimstr("")]
["a", "xx", ""]
["a", "xx", ""]
[(index(","), rindex(",")), indices(",")]
"a,bc,def,ghij,klmno"
[1,13,[1,4,8,13]]
[ index("aba"), rindex("aba"), indices("aba") ]
"xababababax"
[1,7,[1,3,5,7]]
# _strindices is used by indices/1 but is callable
try _strindices("abc") catch .
123
"number (123) cannot be searched, as it is not a string"
try _strindices(123) catch .
"abc"
"number (123) is not a string"
# trim
# \u000b is vertical tab (\v not supported by json)
map(trim), map(ltrim), map(rtrim)
[" \n\t\r\f\u000b", ""," ", "a", " a ", "abc", " abc ", " abc", "abc "]
["", "", "", "a", "a", "abc", "abc", "abc", "abc"]
["", "", "", "a", "a ", "abc", "abc ", "abc", "abc "]
["", "", "", "a", " a", "abc", " abc", " abc", "abc"]
trim, ltrim, rtrim
"\u0009\u000A\u000B\u000C\u000D\u0020\u0085\u00A0\u1680\u2000\u2001\u2002\u2003\u2004\u2005\u2006\u2007\u2008\u2009\u200A\u2028\u2029\u202F\u205F\u3000abc\u0009\u000A\u000B\u000C\u000D\u0020\u0085\u00A0\u1680\u2000\u2001\u2002\u2003\u2004\u2005\u2006\u2007\u2008\u2009\u200A\u2028\u2029\u202F\u205F\u3000"
"abc"
"abc\u0009\u000A\u000B\u000C\u000D\u0020\u0085\u00A0\u1680\u2000\u2001\u2002\u2003\u2004\u2005\u2006\u2007\u2008\u2009\u200A\u2028\u2029\u202F\u205F\u3000"
"\u0009\u000A\u000B\u000C\u000D\u0020\u0085\u00A0\u1680\u2000\u2001\u2002\u2003\u2004\u2005\u2006\u2007\u2008\u2009\u200A\u2028\u2029\u202F\u205F\u3000abc"
try trim catch ., try ltrim catch ., try rtrim catch .
123
"trim input must be a string"
"trim input must be a string"
"trim input must be a string"
indices(1)
[0,1,1,2,3,4,1,5]
[1,2,6]
indices([1,2])
[0,1,2,3,1,4,2,5,1,2,6,7]
[1,8]
indices([1,2])
[1]
[]
indices(", ")
"a,b, cd,e, fgh, ijkl"
[3,9,14]
index("!")
"здравствуй мир!"
14
.[:rindex("x")]
"正xyz"
"正"
indices("o")
"🇬🇧oo"
[2,3]
indices("o")
"ƒoo"
[1,2]
[.[]|split(",")]
["a, bc, def, ghij, jklmn, a,b, c,d, e,f", "a,b,c,d, e,f,g,h"]
[["a"," bc"," def"," ghij"," jklmn"," a","b"," c","d"," e","f"],["a","b","c","d"," e","f","g","h"]]
[.[]|split(", ")]
["a, bc, def, ghij, jklmn, a,b, c,d, e,f", "a,b,c,d, e,f,g,h"]
[["a","bc","def","ghij","jklmn","a,b","c,d","e,f"],["a,b,c,d","e,f,g,h"]]
[.[] * 3]
["a", "ab", "abc"]
["aaa", "ababab", "abcabcabc"]
[.[] * "abc"]
[-1.0, -0.5, 0.0, 0.5, 1.0, 1.5, 3.7, 10.0]
[null,null,"","","abc","abc","abcabcabc","abcabcabcabcabcabcabcabcabcabc"]
[. * (nan,-nan)]
"abc"
[null,null]
. * 100000 | [.[:10],.[-10:]]
"abc"
["abcabcabca","cabcabcabc"]
. * 1000000000
""
""
try (. * 1000000000) catch .
"abc"
"Repeat string result too long"
[.[] / ","]
["a, bc, def, ghij, jklmn, a,b, c,d, e,f", "a,b,c,d, e,f,g,h"]
[["a"," bc"," def"," ghij"," jklmn"," a","b"," c","d"," e","f"],["a","b","c","d"," e","f","g","h"]]
[.[] / ", "]
["a, bc, def, ghij, jklmn, a,b, c,d, e,f", "a,b,c,d, e,f,g,h"]
[["a","bc","def","ghij","jklmn","a,b","c,d","e,f"],["a,b,c,d","e,f,g,h"]]
map(.[1] as $needle | .[0] | contains($needle))
[[[],[]], [[1,2,3], [1,2]], [[1,2,3], [3,1]], [[1,2,3], [4]], [[1,2,3], [1,4]]]
[true, true, true, false, false]
map(.[1] as $needle | .[0] | contains($needle))
[[["foobar", "foobaz"], ["baz", "bar"]], [["foobar", "foobaz"], ["foo"]], [["foobar", "foobaz"], ["blap"]]]
[true, true, false]
[({foo: 12, bar:13} | contains({foo: 12})), ({foo: 12} | contains({})), ({foo: 12, bar:13} | contains({baz:14}))]
{}
[true, true, false]
{foo: {baz: 12, blap: {bar: 13}}, bar: 14} | contains({bar: 14, foo: {blap: {}}})
{}
true
{foo: {baz: 12, blap: {bar: 13}}, bar: 14} | contains({bar: 14, foo: {blap: {bar: 14}}})
{}
false
sort
[42,[2,5,3,11],10,{"a":42,"b":2},{"a":42},true,2,[2,6],"hello",null,[2,5,6],{"a":[],"b":1},"abc","ab",[3,10],{},false,"abcd",null]
[null,null,false,true,2,10,42,"ab","abc","abcd","hello",[2,5,3,11],[2,5,6],[2,6],[3,10],{},{"a":42},{"a":42,"b":2},{"a":[],"b":1}]
(sort_by(.b) | sort_by(.a)), sort_by(.a, .b), sort_by(.b, .c), group_by(.b), group_by(.a + .b - .c == 2)
[{"a": 1, "b": 4, "c": 14}, {"a": 4, "b": 1, "c": 3}, {"a": 1, "b": 4, "c": 3}, {"a": 0, "b": 2, "c": 43}]
[{"a": 0, "b": 2, "c": 43}, {"a": 1, "b": 4, "c": 14}, {"a": 1, "b": 4, "c": 3}, {"a": 4, "b": 1, "c": 3}]
[{"a": 0, "b": 2, "c": 43}, {"a": 1, "b": 4, "c": 14}, {"a": 1, "b": 4, "c": 3}, {"a": 4, "b": 1, "c": 3}]
[{"a": 4, "b": 1, "c": 3}, {"a": 0, "b": 2, "c": 43}, {"a": 1, "b": 4, "c": 3}, {"a": 1, "b": 4, "c": 14}]
[[{"a": 4, "b": 1, "c": 3}], [{"a": 0, "b": 2, "c": 43}], [{"a": 1, "b": 4, "c": 14}, {"a": 1, "b": 4, "c": 3}]]
[[{"a": 1, "b": 4, "c": 14}, {"a": 0, "b": 2, "c": 43}], [{"a": 4, "b": 1, "c": 3}, {"a": 1, "b": 4, "c": 3}]]
unique
[1,2,5,3,5,3,1,3]
[1,2,3,5]
unique
[]
[]
[min, max, min_by(.[1]), max_by(.[1]), min_by(.[2]), max_by(.[2])]
[[4,2,"a"],[3,1,"a"],[2,4,"a"],[1,3,"a"]]
[[1,3,"a"],[4,2,"a"],[3,1,"a"],[2,4,"a"],[4,2,"a"],[1,3,"a"]]
[min,max,min_by(.),max_by(.)]
[]
[null,null,null,null]
.foo[.baz]
{"foo":{"bar":4},"baz":"bar"}
4
.[] | .error = "no, it's OK"
[{"error":true}]
{"error": "no, it's OK"}
[{a:1}] | .[] | .a=999
null
{"a": 999}
to_entries
{"a": 1, "b": 2}
[{"key":"a", "value":1}, {"key":"b", "value":2}]
from_entries
[{"key":"a", "value":1}, {"Key":"b", "Value":2}, {"name":"c", "value":3}, {"Name":"d", "Value":4}]
{"a": 1, "b": 2, "c": 3, "d": 4}
with_entries(.key |= "KEY_" + .)
{"a": 1, "b": 2}
{"KEY_a": 1, "KEY_b": 2}
map(has("foo"))
[{"foo": 42}, {}]
[true, false]
map(has(2))
[[0,1], ["a","b","c"]]
[false, true]
has(nan)
[0,1,2]
false
keys
[42,3,35]
[0,1,2]
[][.]
1000000000000000000
null
map([1,2][0:.])
[-1, 1, 2, 3, 1000000000000000000]
[[1], [1], [1,2], [1,2], [1,2]]
# Test recursive object merge
{"k": {"a": 1, "b": 2}} * .
{"k": {"a": 0,"c": 3}}
{"k": {"a": 0, "b": 2, "c": 3}}
{"k": {"a": 1, "b": 2}, "hello": {"x": 1}} * .
{"k": {"a": 0,"c": 3}, "hello": 1}
{"k": {"a": 0, "b": 2, "c": 3}, "hello": 1}
{"k": {"a": 1, "b": 2}, "hello": 1} * .
{"k": {"a": 0,"c": 3}, "hello": {"x": 1}}
{"k": {"a": 0, "b": 2, "c": 3}, "hello": {"x": 1}}
{"a": {"b": 1}, "c": {"d": 2}, "e": 5} * .
{"a": {"b": 2}, "c": {"d": 3, "f": 9}}
{"a": {"b": 2}, "c": {"d": 3, "f": 9}, "e": 5}
[.[]|arrays]
[1,2,"foo",[],[3,[]],{},true,false,null]
[[],[3,[]]]
[.[]|objects]
[1,2,"foo",[],[3,[]],{},true,false,null]
[{}]
[.[]|iterables]
[1,2,"foo",[],[3,[]],{},true,false,null]
[[],[3,[]],{}]
[.[]|scalars]
[1,2,"foo",[],[3,[]],{},true,false,null]
[1,2,"foo",true,false,null]
[.[]|values]
[1,2,"foo",[],[3,[]],{},true,false,null]
[1,2,"foo",[],[3,[]],{},true,false]
[.[]|booleans]
[1,2,"foo",[],[3,[]],{},true,false,null]
[true,false]
[.[]|nulls]
[1,2,"foo",[],[3,[]],{},true,false,null]
[null]
flatten
[0, [1], [[2]], [[[3]]]]
[0, 1, 2, 3]
flatten(0)
[0, [1], [[2]], [[[3]]]]
[0, [1], [[2]], [[[3]]]]
flatten(2)
[0, [1], [[2]], [[[3]]]]
[0, 1, 2, [3]]
flatten(2)
[0, [1, [2]], [1, [[3], 2]]]
[0, 1, 2, 1, [3], 2]
try flatten(-1) catch .
[0, [1], [[2]], [[[3]]]]
"flatten depth must not be negative"
transpose
[[1], [2,3]]
[[1,2],[null,3]]
transpose
[]
[]
ascii_upcase
"useful but not for é"
"USEFUL BUT NOT FOR é"
bsearch(0,1,2,3,4)
[1,2,3]
-1
0
1
2
-4
bsearch({x:1})
[{ "x": 0 },{ "x": 1 },{ "x": 2 }]
1
try ["OK", bsearch(0)] catch ["KO",.]
"aa"
["KO","string (\"aa\") cannot be searched from"]
strftime("%Y-%m-%dT%H:%M:%SZ")
[2015,2,5,23,51,47,4,63]
"2015-03-05T23:51:47Z"
strftime("%A, %B %d, %Y")
1435677542.822351
"Tuesday, June 30, 2015"
strftime("%Y-%m-%dT%H:%M:%SZ")
[2024,2,15]
"2024-03-15T00:00:00Z"
mktime
[2024,8,21]
1726876800
gmtime
1425599507
[2015,2,5,23,51,47,4,63]
gmtime[5]
1425599507.25
47.25
# test invalid tm input
try strftime("%Y-%m-%dT%H:%M:%SZ") catch .
["a",1,2,3,4,5,6,7]
"strftime/1 requires parsed datetime inputs"
try strflocaltime("%Y-%m-%dT%H:%M:%SZ") catch .
["a",1,2,3,4,5,6,7]
"strflocaltime/1 requires parsed datetime inputs"
try mktime catch .
["a",1,2,3,4,5,6,7]
"mktime requires parsed datetime inputs"
# oss-fuzz #67403: non-string argument with number input fails assert
try ["OK", strftime([])] catch ["KO", .]
0
["KO","strftime/1 requires a string format"]
try ["OK", strflocaltime({})] catch ["KO", .]
0
["KO","strflocaltime/1 requires a string format"]
[strptime("%Y-%m-%dT%H:%M:%SZ")|(.,mktime)]
"2015-03-05T23:51:47Z"
[[2015,2,5,23,51,47,4,63],1425599507]
# Check day-of-week and day of year computations
# (should trip an assert if this fails)
last(range(365 * 67)|("1970-03-01T01:02:03Z"|strptime("%Y-%m-%dT%H:%M:%SZ")|mktime) + (86400 * .)|strftime("%Y-%m-%dT%H:%M:%SZ")|strptime("%Y-%m-%dT%H:%M:%SZ"))
null
[2037,1,11,1,2,3,3,41]
# module system
import "a" as foo; import "b" as bar; def fooa: foo::a; [fooa, bar::a, bar::b, foo::a]
null
["a","b","c","a"]
import "c" as foo; [foo::a, foo::c]
null
[0,"acmehbah"]
include "c"; [a, c]
null
[0,"acmehbah"]
import "data" as $e; import "data" as $d; [$d[].this,$e[].that,$d::d[].this,$e::e[].that]|join(";")
null
"is a test;is too;is a test;is too"
# Regression test for #2000
import "data" as $a; import "data" as $b; def f: {$a, $b}; f
null
{"a":[{"this":"is a test","that":"is too"}],"b":[{"this":"is a test","that":"is too"}]}
include "shadow1"; e
null
2
include "shadow1"; include "shadow2"; e
null
3
import "shadow1" as f; import "shadow2" as f; import "shadow1" as e; [e::e, f::e]
null
[2,3]
%%FAIL
module (.+1); 0
jq: error: Module metadata must be constant at <top-level>, line 1, column 8:
module (.+1); 0
^^^^^
%%FAIL
module []; 0
jq: error: Module metadata must be an object at <top-level>, line 1, column 8:
module []; 0
^^
%%FAIL
include "a" (.+1); 0
jq: error: Module metadata must be constant at <top-level>, line 1, column 13:
include "a" (.+1); 0
^^^^^
%%FAIL
include "a" []; 0
jq: error: Module metadata must be an object at <top-level>, line 1, column 13:
include "a" []; 0
^^
%%FAIL
include "\ "; 0
jq: error: Invalid escape at line 1, column 4 (while parsing '"\ "') at <top-level>, line 1, column 10:
include "\ "; 0
^^
%%FAIL
include "\(a)"; 0
jq: error: Import path must be constant at <top-level>, line 1, column 9:
include "\(a)"; 0
^^^^^^
modulemeta
"c"
{"whatever":null,"deps":[{"as":"foo","is_data":false,"relpath":"a"},{"search":"./","as":"d","is_data":false,"relpath":"d"},{"search":"./","as":"d2","is_data":false,"relpath":"d"},{"search":"./../lib/jq","as":"e","is_data":false,"relpath":"e"},{"search":"./../lib/jq","as":"f","is_data":false,"relpath":"f"},{"as":"d","is_data":true,"relpath":"data"}],"defs":["a/0","c/0"]}
modulemeta | .deps | length
"c"
6
modulemeta | .defs | length
"c"
2
%%FAIL IGNORE MSG
import "syntaxerror" as e; .
jq: error: syntax error, unexpected ';', expecting end of file at tests/modules/syntaxerror/syntaxerror.jq, line 1, column 4:
wat;
^
%%FAIL
%::wat
jq: error: syntax error, unexpected '%', expecting end of file at <top-level>, line 1, column 1:
%::wat
^
import "test_bind_order" as check; check::check
null
true
try -. catch .
"very-long-long-long-long-string"
"string (\"very-long-long-long-long...\") cannot be negated"
try (.-.) catch .
"very-long-long-long-long-string"
"string (\"very-long-long-long-long...\") and string (\"very-long-long-long-long...\") cannot be subtracted"
"x" * range(0; 12; 2) + "☆" * 8 | try -. catch .
null
"string (\"☆☆☆☆☆☆☆☆\") cannot be negated"
"string (\"xx☆☆☆☆☆☆☆☆\") cannot be negated"
"string (\"xxxx☆☆☆☆☆☆...\") cannot be negated"
"string (\"xxxxxx☆☆☆☆☆☆...\") cannot be negated"
"string (\"xxxxxxxx☆☆☆☆☆...\") cannot be negated"
"string (\"xxxxxxxxxx☆☆☆☆...\") cannot be negated"
try (. + "x") catch . == if have_decnum then "number (12345678901234567890123456...) and string (\"x\") cannot be added" else "number (12345678901234568000000000...) and string (\"x\") cannot be added" end
123456789012345678901234567890
true
join(",")
["1",2,true,false,3.4]
"1,2,true,false,3.4"
.[] | join(",")
[[], [null], [null,null], [null,null,null]]
""
""
","
",,"
.[] | join(",")
[["a",null], [null,"a"]]
"a,"
",a"
try join(",") catch .
["1","2",{"a":{"b":{"c":33}}}]
"string (\"1,2,\") and object ({\"a\":{\"b\":{\"c\":33}}}) cannot be added"
try join(",") catch .
["1","2",[3,4,5]]
"string (\"1,2,\") and array ([3,4,5]) cannot be added"
{if:0,and:1,or:2,then:3,else:4,elif:5,end:6,as:7,def:8,reduce:9,foreach:10,try:11,catch:12,label:13,import:14,include:15,module:16}
null
{"if":0,"and":1,"or":2,"then":3,"else":4,"elif":5,"end":6,"as":7,"def":8,"reduce":9,"foreach":10,"try":11,"catch":12,"label":13,"import":14,"include":15,"module":16}
try (1/.) catch .
0
"number (1) and number (0) cannot be divided because the divisor is zero"
try (1/0) catch .
0
"number (1) and number (0) cannot be divided because the divisor is zero"
try (0/0) catch .
0
"number (0) and number (0) cannot be divided because the divisor is zero"
try (1%.) catch .
0
"number (1) and number (0) cannot be divided (remainder) because the divisor is zero"
try (1%0) catch .
0
"number (1) and number (0) cannot be divided (remainder) because the divisor is zero"
# Basic numbers tests: integers, powers of two
[range(-52;52;1)] as $powers | [$powers[]|pow(2;.)|log2|round] == $powers
null
true
[range(-99/2;99/2;1)] as $orig | [$orig[]|pow(2;.)|log2] as $back | ($orig|keys)[]|. as $k | (($orig|.[$k])-($back|.[$k]))|if . < 0 then . * -1 else . end|select(.>.00005)
null
%%FAIL
{
jq: error: syntax error, unexpected end of file at <top-level>, line 1, column 1:
{
^
%%FAIL
}
jq: error: syntax error, unexpected INVALID_CHARACTER, expecting end of file at <top-level>, line 1, column 1:
}
^
(.[{}] = 0)?
null
INDEX(range(5)|[., "foo\(.)"]; .[0])
null
{"0":[0,"foo0"],"1":[1,"foo1"],"2":[2,"foo2"],"3":[3,"foo3"],"4":[4,"foo4"]}
JOIN({"0":[0,"abc"],"1":[1,"bcd"],"2":[2,"def"],"3":[3,"efg"],"4":[4,"fgh"]}; .[0]|tostring)
[[5,"foo"],[3,"bar"],[1,"foobar"]]
[[[5,"foo"],null],[[3,"bar"],[3,"efg"]],[[1,"foobar"],[1,"bcd"]]]
range(5;10)|IN(range(10))
null
true
true
true
true
true
range(5;13)|IN(range(0;10;3))
null
false
true
false
false
true
false
false
false
range(10;12)|IN(range(10))
null
false
false
IN(range(10;20); range(10))
null
false
IN(range(5;20); range(10))
null
true
# Regression test for #1347
(.a as $x | .b) = "b"
{"a":null,"b":null}
{"a":null,"b":"b"}
# Regression test for #1368
(.. | select(type == "object" and has("b") and (.b | type) == "array")|.b) |= .[0]
{"a": {"b": [1, {"b": 3}]}}
{"a": {"b": 1}}
isempty(empty)
null
true
isempty(range(3))
null
false
isempty(1,error("foo"))
null
false
# Regression test for #1815
index("")
""
null
# check that dead code removal occurs after builtin it generation
builtins|length > 10
null
true
"-1"|IN(builtins[] / "/"|.[1])
null
false
all(builtins[] / "/"; .[1]|tonumber >= 0)
null
true
builtins|any(.[:1] == "_")
null
false
## Test ability to use keywords (uncomment after eval is pushed)
#(.[] as $kw | "\"{\($kw)} as $\($kw) | $\($kw) | {$\($kw)} | {\($kw):.\($kw)}\""|eval|empty),null
#["as","def","module","import","include","if","then","else","elif","end","reduce","foreach","and","or","try","catch","label","break","__loc__"]
#null
#
#(.[] as $kw | "\"def f($\($kw)): $\($kw); f(.)\""|eval|empty),null
#["as","def","module","import","include","if","then","else","elif","end","reduce","foreach","and","or","try","catch","label","break","__loc__"]
#null
#
# Tests to cover the new toliteral number functionality
# For an example see #1652 and other linked issues
#
# We are backward and sanity compatible
map(. == 1)
[1, 1.0, 1.000, 100e-2, 1e+0, 0.0001e4]
[true, true, true, true, true, true]
# When no arithmetic is involved jq should preserve the literal value
.[0] | tostring | . == if have_decnum then "13911860366432393" else "13911860366432392" end
[13911860366432393]
true
.x | tojson | . == if have_decnum then "13911860366432393" else "13911860366432392" end
{"x":13911860366432393}
true
(13911860366432393 == 13911860366432392) | . == if have_decnum then false else true end
null
true
# Applying arithmetic to the value will truncate the result to double
. - 10
13911860366432393
13911860366432382
.[0] - 10
[13911860366432393]
13911860366432382
.x - 10
{"x":13911860366432393}
13911860366432382
# Unary negation preserves numerical precision
-. | tojson == if have_decnum then "-13911860366432393" else "-13911860366432392" end
13911860366432393
true
-. | tojson == if have_decnum then "0.12345678901234567890123456789" else "0.12345678901234568" end
-0.12345678901234567890123456789
true
[1E+1000,-1E+1000 | tojson] == if have_decnum then ["1E+1000","-1E+1000"] else ["1.7976931348623157e+308","-1.7976931348623157e+308"] end
null
true
. |= try . catch .
1
1
# decnum to double conversion
.[] as $n | $n+0 | [., tostring, . == $n]
[-9007199254740993, -9007199254740992, 9007199254740992, 9007199254740993, 13911860366432393]
[-9007199254740992,"-9007199254740992",true]
[-9007199254740992,"-9007199254740992",true]
[9007199254740992,"9007199254740992",true]
[9007199254740992,"9007199254740992",true]
[13911860366432392,"13911860366432392",true]
# abs, fabs, length
abs
"abc"
"abc"
map(abs)
[-0, 0, -10, -1.1]
[0,0,10,1.1]
map(fabs)
[-0, 0, -10, -1.1]
[0,0,10,1.1]
map(abs == length) | unique
[-10, -1.1, -1e-1, 1000000000000000002]
[true]
# The following is NOT prescriptive:
map(abs)
[0.1,1000000000000000002]
[1e-1, 1000000000000000002]
[1E+1000,-1E+1000 | abs | tojson] | unique == if have_decnum then ["1E+1000"] else ["1.7976931348623157e+308"] end
null
true
[1E+1000,-1E+1000 | length | tojson] | unique == if have_decnum then ["1E+1000"] else ["1.7976931348623157e+308"] end
null
true
# Using a keyword as variable/label name
123 as $label | $label
null
123
[ label $if | range(10) | ., (select(. == 5) | break $if) ]
null
[0,1,2,3,4,5]
reduce .[] as $then (4 as $else | $else; . as $elif | . + $then * $elif)
[1,2,3]
96
1 as $foreach | 2 as $and | 3 as $or | { $foreach, $and, $or, a }
{"a":4,"b":5}
{"foreach":1,"and":2,"or":3,"a":4}
[ foreach .[] as $try (1 as $catch | $catch - 1; . + $try; .) ]
[10,9,8,7]
[10,19,27,34]
# Object construction
{ a, $__loc__, c }
{"a":[1,2,3],"b":"foo","c":{"hi":"hey"}}
{"a":[1,2,3],"__loc__":{"file":"<top-level>","line":1},"c":{"hi":"hey"}}
1 as $x | "2" as $y | "3" as $z | { $x, as, $y: 4, ($z): 5, if: 6, foo: 7 }
{"as":8}
{"x":1,"as":8,"2":4,"3":5,"if":6,"foo":7}
# nan is parsed as a valid NaN value from JSON
fromjson | isnan
"nan"
true
tojson | fromjson
{"a":nan}
{"a":null}
# NaN with payload is not parsed
.[] | try (fromjson | isnan) catch .
["NaN","-NaN","NaN1","NaN10","NaN100","NaN1000","NaN10000","NaN100000"]
true
true
"Invalid numeric literal at EOF at line 1, column 4 (while parsing 'NaN1')"
"Invalid numeric literal at EOF at line 1, column 5 (while parsing 'NaN10')"
"Invalid numeric literal at EOF at line 1, column 6 (while parsing 'NaN100')"
"Invalid numeric literal at EOF at line 1, column 7 (while parsing 'NaN1000')"
"Invalid numeric literal at EOF at line 1, column 8 (while parsing 'NaN10000')"
"Invalid numeric literal at EOF at line 1, column 9 (while parsing 'NaN100000')"
# calling input/0, or debug/0 in a test doesn't crash jq
try input catch .
null
"break"
debug
1
1
# try/catch catches more than it should #1859
"foo" | try ((try . catch "caught too much") | error) catch "caught just right"
null
"caught just right"
.[]|(try (if .=="hi" then . else error end) catch empty) | "\(.) there!"
["hi","ho"]
"hi there!"
try (["hi","ho"]|.[]|(try . catch (if .=="ho" then "BROKEN"|error else empty end)) | if .=="ho" then error else "\(.) there!" end) catch "caught outside \(.)"
null
"hi there!"
"caught outside ho"
.[]|(try . catch (if .=="ho" then "BROKEN"|error else empty end)) | if .=="ho" then error else "\(.) there!" end
["hi","ho"]
"hi there!"
try (try error catch "inner catch \(.)") catch "outer catch \(.)"
"foo"
"inner catch foo"
try ((try error catch "inner catch \(.)")|error) catch "outer catch \(.)"
"foo"
"outer catch inner catch foo"
# Also #1859, but from #1885
first(.?,.?)
null
null
# Also #1859, but from #2140
{foo: "bar"} | .foo |= .?
null
{"foo": "bar"}
# Also #1859, but from #2220
. |= try 2
1
2
. |= try 2 catch 3
1
2
.[] |= try tonumber
["1", "2a", "3", " 4", "5 ", "6.7", ".89", "-876", "+5.43", 21]
[1, 3, 6.7, 0.89, -876, 5.43, 21]
# Also 1859, but from 2073
any(keys[]|tostring?;true)
{"a":"1","b":"2","c":"3"}
true
# explode/implode
# test replacement character (65533) for outside codepoint range and 0xd800 (55296) - 0xdfff (57343) utf16 surrogate pair range
# 1.1 and 1.9 to test round down of non-ints
implode|explode
[-1,0,1,2,3,1114111,1114112,55295,55296,57343,57344,1.1,1.9]
[65533,0,1,2,3,1114111,65533,55295,65533,65533,57344,1,1]
map(try implode catch .)
[123,["a"],[nan]]
["implode input must be an array","string (\"a\") can't be imploded, unicode codepoint needs to be numeric","number (null) can't be imploded, unicode codepoint needs to be numeric"]
try 0[implode] catch .
[]
"Cannot index number with string (\"\")"
# walk
walk(.)
{"x":0}
{"x":0}
walk(1)
{"x":0}
1
# The following is a regression test, not a requirement:
[walk(.,1)]
{"x":0}
[{"x":0},1]
# Issue #2584
walk(select(IN({}, []) | not))
{"a":1,"b":[]}
{"a":1}
# #2815
[range(10)] | .[1.2:3.5]
null
[1,2,3]
[range(10)] | .[1.5:3.5]
null
[1,2,3]
[range(10)] | .[1.7:3.5]
null
[1,2,3]
[range(10)] | .[1.7:4294967295]
null
[1,2,3,4,5,6,7,8,9]
[range(10)] | .[1.7:-4294967296]
null
[]
[[range(10)] | .[1.1,1.5,1.7]]
null
[1,1,1]
[range(5)] | .[1.1] = 5
null
[0,5,2,3,4]
[range(3)] | .[nan:1]
null
[0]
[range(3)] | .[1:nan]
null
[1,2]
[range(3)] | .[nan]
null
null
try ([range(3)] | .[nan] = 9) catch .
null
"Cannot set array element at NaN index"
try ("foobar" | .[1.5:3.5] = "xyz") catch .
null
"Cannot update string slices"
try ([range(10)] | .[1.5:3.5] = ["xyz"]) catch .
null
[0,"xyz",4,5,6,7,8,9]
try ("foobar" | .[1.5]) catch .
null
"Cannot index string with number (1.5)"
# setpath/2 does not leak the input after an invalid get #2970
try ["ok", setpath([1]; 1)] catch ["ko", .]
{"hi":"hello"}
["ko","Cannot index object with number (1)"]
try fromjson catch .
"{'a': 123}"
"Invalid string literal; expected \", but got ' at line 1, column 5 (while parsing '{'a': 123}')"
# ltrimstr/1 rtrimstr/1 don't leak on invalid input #2977
try ltrimstr(1) catch "x", try rtrimstr(1) catch "x" | "ok"
"hi"
"ok"
"ok"
try ltrimstr("x") catch "x", try rtrimstr("x") catch "x" | "ok"
{"hey":[]}
"ok"
"ok"
# ltrimstr/1 and rtrimstr/1 return an error for non-strings. #2969
.[] as [$x, $y] | try ["ok", ($x | ltrimstr($y))] catch ["ko", .]
[["hi",1],[1,"hi"],["hi","hi"],[1,1]]
["ko","startswith() requires string inputs"]
["ko","startswith() requires string inputs"]
["ok",""]
["ko","startswith() requires string inputs"]
.[] as [$x, $y] | try ["ok", ($x | rtrimstr($y))] catch ["ko", .]
[["hi",1],[1,"hi"],["hi","hi"],[1,1]]
["ko","endswith() requires string inputs"]
["ko","endswith() requires string inputs"]
["ok",""]
["ko","endswith() requires string inputs"]
# oss-fuzz #66061: setpath/2 leaks when indexing array with array
try ["OK", setpath([[1]]; 1)] catch ["KO", .]
[]
["KO","Cannot update field at array index of array"]
# regression test for #3227
foreach .[] as $x (0, 1; . + $x)
[1, 2]
1
3
2
4
# regression test for CVE-2025-49014 (use of fmt after free)
# tests with both empty string literal and empty string created by function
# as they seems to behave reference wise differently.
strflocaltime("" | ., @uri)
0
""
""
# regression tests for #3413
# upper range bounds should be in sync with the constants defined at
# src/jv_parse.c:#define MAX_PARSING_DEPTH (N)
# src/jv_print.c:#define MAX_PRINT_DEPTH (N)
# (N-1)
reduce range(9999) as $_ ([];[.]) | tojson | fromjson | flatten
null
[]
# (N)
reduce range(10000) as $_ ([];[.]) | tojson | try (fromjson) catch . | (contains("<skipped: too deep>") | not) and contains("Exceeds depth limit for parsing")
null
true
# (N+1)
reduce range(10001) as $_ ([];[.]) | tojson | contains("<skipped: too deep>")
null
true
# regression test for CVE-2026-33947
setpath([range(10000) | 0]; 0) | flatten
null
[0]
try setpath([range(10001) | 0]; 0) catch .
null
"Path too deep"
getpath([range(10000) | 0])
null
null
try getpath([range(10001) | 0]) catch .
null
"Path too deep"
delpaths([[range(10000) | 0]])
null
null
try delpaths([[range(10001) | 0]]) catch .
null
"Path too deep"
# regression test for CVE-2026-40612
reduce range(10000) as $_ ([]; [.]) | contains([[]])
null
true
try (reduce range(10001) as $_ ([]; [.]) as $x | $x | contains($x)) catch .
null
"Containment check too deep"
# regression test for CVE-2026-43896
reduce range(10000) as $_ ({}; {a: .}) as $x | $x * $x | length
null
1
try (reduce range(10001) as $_ ({}; {a: .}) as $x | $x * $x) catch .
null
"Object merge too deep"
# regression test for deep structural equality recursion
try ((reduce range(10001) as $_ ([]; [.])) as $x | (reduce range(10001) as $_ ([]; [.])) as $y | $x == $y) catch .
null
"Equality check too deep"
# regression tests for deep ordering comparisons
try ((reduce range(10001) as $_ ([]; [.])) as $x | [$x, $x] | sort) catch .
null
"Comparison too deep"
try ((reduce range(10001) as $_ ([]; [.])) as $x | [$x, $x] | unique) catch .
null
"Comparison too deep"
try ((reduce range(10001) as $_ ({}; {a: .})) as $x | [$x, $x] | sort) catch .
null
"Comparison too deep"
try ((reduce range(10001) as $_ ({}; {a: .})) as $x | [$x, $x] | unique) catch .
null
"Comparison too deep"</pblock>
<pblock filename="ARCHITECTURE_compact.md" role="context" path="/mnt/c/Users/barlo/projects/drydock/uat/jq/runs/20260822.044627/workspace/targets/jq/blueprint/ARCHITECTURE_compact.md">
<!-- Compacted from ARCHITECTURE.md sha256=f0e07d8104b7c23be2772201e83dfaf382f4c295492da7b8ec72b2a914af633b on 2026-08-22 by drydock build agent -->
- Executable: `./jq -c '<program>'`; compact JSON lines on stdout.
- Exit codes: `0` success, `3` compile failure, `5` runtime failure; diagnostics on stderr.
- Standard-library Python only; no external jq, dependencies, networking, or persistence.
- Modules: CLI, lexer, parser/AST, evaluator streams, runtime values, builtins, paths/assignment, diagnostics.
- Preserve generator ordering, multiplicity, backtracking, immutable transformations, and partial output.</pblock>
IMPLEMENTS - Authoritative Step Specifications
<pblock label="Implementation recency anchor" kind="section"> The files in this section are the load-bearing specifications for this build block. Build these files exactly. Treat earlier sections as constraints and context.
</pblock>
<pblock filename="FEATURE-FLOW-005.md" role="implements" path="/mnt/c/Users/barlo/projects/drydock/uat/jq/runs/20260822.044627/workspace/targets/jq/blueprint/FEATURE-FLOW-005.md" guidance="Feature Specification">
# FEATURE: Reductions and Iteration Controls
| Field | Value |
|-------------|-------|
| Version | 20260822 V1 |
| Description | Provides jq reductions and generator iteration-control builtins. |
| Depends On | ARCHITECTURE.md, FEATURE-FLOW-004.md |
| Provides | reduce, foreach, range, limit, skip, first, last, nth |
| Consumes | ordered generator evaluator, lexical labels, variable bindings |
## Workflow
Reduction and iteration controls consume ordered generator streams and preserve jq's state, ordering, Cartesian argument, backtracking, and short-circuit semantics.
- `reduce EXP as $var (INIT; UPDATE)` accumulates each generated value.
- `foreach EXP as $var (INIT; UPDATE; EXTRACT)` emits intermediate extracted values.
- `range` supports one, two, and three argument forms.
- `limit`, `skip`, `first`, `last`, and `nth` operate on generated streams.
- Invalid negative counts for `limit`, `skip`, and `nth` raise runtime errors.
## Programmatic Acceptance
=== AC flow-005-conformance ===
Intent: The executable passes the authoritative conformance cases exercising reductions and iteration controls.
Suite: scoped
Requires: executable=python3; scope=test
import json
import os
import subprocess
import sys
SELECT = r"reduce|foreach|limit|skip|nth|first|last"
result = subprocess.run(
[sys.executable, "sources/run_conformance.py", "--select", SELECT, "--json"],
capture_output=True,
text=True,
env={**os.environ, "JQ": f"{os.getcwd()}/jq"},
)
print(result.stdout)
print(result.stderr, file=sys.stderr)
report = json.loads(result.stdout)
tally = report["summary"]
assert sum(tally.values()) > 0
assert tally["fail"] == 0 and tally["error"] == 0
assert result.returncode == 0
=== END AC flow-005-conformance ===
## User Acceptance
- Reduction and iteration filters preserve output ordering and generator multiplicity.
## Guardrails
- Do not replace generator evaluation with single-value evaluation.
- Preserve runtime errors and partial output semantics.</pblock>
<pblock label="Build instructions" kind="instructions">
Build instructions for this block
Implement reductions and iteration controls. (FLOW-005)
Implement reducer state, foreach extraction, range variants, limit, skip, first, last, and nth with Cartesian arguments, backtracking, and short-circuiting.
</pblock>
Agent Task
You are a Drydock build agent implementing exactly one build step of a larger plan. The build job block below names the target, the build working directory, and the step. Everything you need is stacked into this prompt under role headings:
compass— the Target's COMPASS.md orientation.implements— the Typed Specification files this step builds. These are
authoritative; implement them exactly.
context— read-only support specifications. Do not reimplement them.stack— enterprise stack and technology rules. Honor them.rules— governance and branding rules. Honor them.
Operating contract:
- Follow the write authorization and protected paths in the stacked
COMPASS.mdexactly.
That persisted guardrail is the sole authority for paths this build may modify.
- Start by inspecting the build working directory. Preserve existing application
files unless this step's specifications require a change. Its sources/ subdirectory holds staged build assets — imported test corpora, conformance harnesses, and fixtures — placed there for you. They are read-only inputs: run them, import them, and write code against them, but never create, rewrite, trim, regenerate, or substitute one, even to make a check pass. A step that modifies a staged asset fails and the asset is restored. If an asset you expect is absent, report that; do not author a replacement.
- Implement only this step. Use
context,stack, andrulesas constraints,
not as additional work to perform.
- Follow the stack and rules for languages, structure, naming, and branding.
- The programmatic acceptance assertions in the
implementsspecifications are
this step's Definition of Done — human-owned, declared before the build, and fixed. Build the story and, in this same step, write the deterministic tests that prove each declared assertion, as a TDD master would; add finer tests for coverage. Every test you write follows the same rule the acceptance assertions do: act on the system, read the state back, compare to expected. The oracle is a return value, parsed JSON, a status code, a stored row, file contents read back, or an exit status — never a substring of captured stdout or stderr, a test-runner tally, or a log line. Write tests in the project's own language using that language's libraries; an in-language HTTP client yields a status code and a parsed body, where curl yields text to scrape. Round-trip anything that stores state: act, then read back through the public interface. Assert declared failure signals on negative paths, never message wording. You may add tests but must never remove, soften, or weaken a declared acceptance assertion. A Suite: full conformance check gates on the entire imported test suite: the step is done only when it passes in full, never on a representative subset — reproduce the standard exactly rather than wrapping a third-party library that approximates it. For a suite, the runner's exit status is the verdict and the whole verdict: print its captured output for diagnosis, never assert on the text of its summary. When an assertion is a static or filesystem scan (import boundary, "X never appears outside Y," grep/AST gate), honor the scope the specification states and never widen it: scan production source only, exclude .venv/, site-packages, and vendored or generated code, and do not flag test doubles or fixtures that use the guarded dependency. Run every declared acceptance assertion before returning. For a conformance suite, use its section or example filters to diagnose coherent root-cause clusters, but rerun the full declared scope before reporting the result. Treat failing examples as a work queue for fixing general behavior; never add example-specific exceptions.
- Grow the project's own test suite as you write the code, and treat it as the project's
real coverage. The acceptance assertions in implements are gates: few, fixed, and written before any code existed, so every expectation in them is a prediction. The tests you write are written beside the finished code, so their expected values are observed rather than predicted — which is why exhaustive coverage belongs here and not there. Extend the suite in the project's established location and runner, keep it runnable by the project's declared test command, and leave it green when you return. Cover, at minimum: every public entry point and every verb it declares, including declared error paths; the boundaries — empty, exactly one, many, absent optional fields, declared maxima; declared idempotence, applied twice; one behavior per test, named for the behavior; and isolation — each test arranges its own data, with a fresh store or explicit teardown, so a run leaves no residue behind in the build directory. Where a staged authoritative suite already covers a surface, that suite is the coverage: run it, and do not restate its cases. Run it only through the invocation this step's acceptance criteria declare. A criterion marked Suite: scoped names the whole of this step's obligation to that suite; running the suite's unscoped entry point instead is not extra rigor, it is a different step's gate executed early. A partial capability fails most of an authoritative corpus by construction and its unimplemented cases exhaust the runner's per-case timeout rather than returning, so the unscoped run costs the most where it teaches the least, and interrupting it forfeits the step. If no criterion in this step invokes the staged suite, do not invoke it. Report the pass/fail counts of the invocations you did run in your SUMMARY so a reader can see coverage moving across steps.
- Treat
User Acceptanceentries as review evidence requirements. Implement
the supporting behavior, but do not claim to have performed human judgment.
- The
implementssection is authoritative and intentionally stacked late in
the prompt as the recency anchor. Build that WHAT exactly; do not substitute generic framework defaults.
- Before adding or installing Python dependencies, verify each package name
against the declared registry. Do not invent package names. If a needed package cannot be verified or appears newly published, fail explicitly instead of installing it.
- Use the stack's required package manager workflow for dependency changes.
When the stack requires uv, update manifests through uv conventions rather than bare pip install.
- Do not claim success unless you actually created or modified project files in
the build working directory. If you cannot write files or cannot complete the step, report failure explicitly.
- Do not run
git add,git commit, create branches, create tags, rewrite
history, or otherwise mutate Git history. Drydock owns the final build directory commit after you return.
- End your response with this exact closing structure:
RESULT: SUCCESS | FAILED
FILES CHANGED:
- relative/path
SUMMARY:
<brief reviewable summary>
BLOCKERS:
- <only if any>Before RESULT, you may emit one optional JSON payload when implementation required a bounded choice not already settled by the owning specification. This records what you did; it does not ask permission, create a questionnaire, or excuse incomplete work:
<blueprint-decisions>
[{"spec":"FEATURE-Example.md","severity":"Material","subject":"Chosen behavior","decision":"Options A and B were available. I implemented B because ... Is that acceptable, or should this change on replan?"}]
</blueprint-decisions>Name only a specification implemented by this build block. Use Low or Material; Build never emits a Blocking decision. Omit the payload when no implementation decision was necessary.
FILES CHANGEDmust list only files actually written in the build working
directory. If no files were written, use RESULT: FAILED.
- On
RESULT: FAILED, append two additional lines so the failure is actionable
without opening logs. FAILURE_SUMMARY is one line naming the cause; FAILURE_DETAIL states what happened, why, and what to change before a rerun. Name concrete conditions when they apply: token or context limit exceeded, could not execute commands in this environment, a required input was missing, or a specific tool or command failed.
FAILURE_SUMMARY: <one line naming the cause>
FAILURE_DETAIL: <what happened, why, and what to change before rerunning>- When a declared acceptance criterion cannot pass no matter how the code is written,
say so with this exact token. You may not edit the criterion — it is staged and restored before grading:
AC_BROKEN: <check-id>[, <check-id>]This is a report, not a verdict, and it stops nothing. A criterion reaches you only when its expected value is one its author could not have invented — a status code, a staged suite's exit status, a value the criterion itself supplied as input — so your claim that the criterion rather than the code is at fault is the less likely explanation, and the budget is spent as it would be for any other failure. A criterion whose expectation was hand-typed already settles DISPUTED on its own, without you naming it. Emit the token only after running the criterion and confirming the underlying command succeeded while the assertion still failed. Name the affected check ids, emit it alongside your normal RESULT line, state the reasoning in FAILURE_DETAIL, and emit it even when RESULT: SUCCESS. Do not use it for a criterion you merely failed to satisfy.