=== BEGIN ARTIFACT FEATURE-CORE-003.md ===
# FEATURE: Core Runtime Errors and Optional Evaluation

| Field       | Value |
|-------------|-------|
| Version     | 20260822 V1 |
| Description | Defines empty streams, runtime errors, optional evaluation, try/catch, and partial output behavior. |
| Depends On  | ARCHITECTURE.md, FEATURE-CORE-002.md |
| Provides    | empty, error, ?, try/catch, partial runtime output |
| Consumes    | ordered generator evaluator |

## Questions

- None.

## Intent

Runtime failures are distinct from compile failures. Filters may suppress errors with `?` or `try`, and values emitted before an uncaught runtime error remain observable.

## Behavior

- `empty` produces no values.
- `error` raises a runtime error.
- `EXP?` suppresses errors from `EXP`.
- `try EXP catch HANDLER` evaluates `HANDLER` with the error value.
- Uncaught runtime errors terminate with exit code 5 after preserving prior output.

## Programmatic Acceptance

=== AC core-003-scoped-conformance ===
Intent: The authoritative corpus cases exercising try, error, and optional evaluation execute successfully.
Suite: scoped
Requires: executable=python3; scope=test

import json
import os
import subprocess
import sys

selector = r"try|error|\?"
result = subprocess.run(
    [sys.executable, "sources/run_conformance.py", "--select", selector, "--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)
summary = report["summary"]
assert sum(summary.values()) > 0
assert summary["fail"] == 0
assert summary["error"] == 0
assert result.returncode == 0
=== END AC core-003-scoped-conformance ===

=== AC core-003-runtime-slice ===
Intent: Corpus cases containing explicit runtime errors are accepted with jq runtime semantics.
Suite: scoped
Requires: executable=python3; scope=test

import json
import os
import subprocess
import sys

selector = r"error"
result = subprocess.run(
    [sys.executable, "sources/run_conformance.py", "--select", selector, "--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)
summary = report["summary"]
assert sum(summary.values()) > 0
assert summary["fail"] == 0 and summary["error"] == 0
assert result.returncode == 0
=== END AC core-003-runtime-slice ===

## User Acceptance

- None.

## Guardrails

- Runtime errors must not be reported as compile failures.
- Diagnostics must be written to stderr.

=== BEGIN ARTIFACT FEATURE-CORE-004.md ===
# FEATURE: jq Truthiness and Comparison Semantics

| Field       | Value |
|-------------|-------|
| Version     | 20260822 V1 |
| Description | Defines jq truthiness, equality, inequality, and total ordering semantics. |
| Depends On  | ARCHITECTURE.md, FEATURE-CORE-003.md |
| Provides    | truthiness, equality, inequality, comparison ordering |
| Consumes    | ordered generator evaluator |

## Questions

- None.

## Intent

Only `false` and `null` are falsey. Comparisons are structural, distinguish booleans from numbers, treat numerically equivalent values equally, and follow jq's total type ordering.

## Behavior

- Conditional truthiness recognizes only `false` and `null` as false.
- Equality ignores object key order and equates numerically equivalent numbers.
- Boolean and numeric values remain distinct.
- `<`, `<=`, `>`, and `>=` use jq's ordering across all JSON value types.

## Programmatic Acceptance

=== AC core-004-comparison-conformance ===
Intent: The authoritative corpus comparison cases execute successfully.
Suite: scoped
Requires: executable=python3; scope=test

import json
import os
import subprocess
import sys

selector = r"==|!=|<=|>=|<|>"
result = subprocess.run(
    [sys.executable, "sources/run_conformance.py", "--select", selector, "--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)
summary = report["summary"]
assert sum(summary.values()) > 0
assert summary["fail"] == 0
assert summary["error"] == 0
assert result.returncode == 0
=== END AC core-004-comparison-conformance ===

=== AC core-004-truthiness-slice ===
Intent: The authoritative corpus truthiness and boolean-operator cases execute successfully.
Suite: scoped
Requires: executable=python3; scope=test

import json
import os
import subprocess
import sys

selector = r"if |and|or|not"
result = subprocess.run(
    [sys.executable, "sources/run_conformance.py", "--select", selector, "--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)
summary = report["summary"]
assert sum(summary.values()) > 0
assert summary["fail"] == 0 and summary["error"] == 0
assert result.returncode == 0
=== END AC core-004-truthiness-slice ===

## User Acceptance

- None.

## Guardrails

- Python truthiness must not replace jq truthiness.
- Boolean values must never compare equal to numeric values.

=== BEGIN ARTIFACT FEATURE-VALUE-001.md ===
# FEATURE: jq Value and Numeric Model

| Field       | Value |
|-------------|-------|
| Version     | 20260822 V1 |
| Description | Defines jq JSON values, special numeric values, literal-number handling, and serialization. |
| Depends On  | ARCHITECTURE.md, FEATURE-CORE-004.md |
| Provides    | null, boolean, number, string, array, object, NaN, infinity values |
| Consumes    | JSON input reader |

## Questions

- None.

## Intent

The interpreter represents all jq value kinds, including NaN and infinity, while preserving the observable numeric behavior required by the corpus and serializing values as valid JSON output.

## Behavior

- JSON null, booleans, numbers, strings, arrays, and objects are supported.
- `nan` and `infinite` are numeric jq values.
- Numeric equality and arithmetic follow jq's numeric semantics.
- JSON serialization handles special numeric values according to jq behavior.

## Programmatic Acceptance

=== AC value-001-numeric-conformance ===
Intent: The authoritative corpus numeric, NaN, infinity, and JSON conversion cases execute successfully.
Suite: scoped
Requires: executable=python3; scope=test

import json
import os
import subprocess
import sys

selector = r"nan|infinite|tojson|fromjson"
result = subprocess.run(
    [sys.executable, "sources/run_conformance.py", "--select", selector, "--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)
summary = report["summary"]
assert sum(summary.values()) > 0
assert summary["fail"] == 0
assert summary["error"] == 0
assert result.returncode == 0
=== END AC value-001-numeric-conformance ===

=== AC value-001-type-slice ===
Intent: The authoritative corpus cases covering jq value kinds and numeric predicates execute successfully.
Suite: scoped
Requires: executable=python3; scope=test

import json
import os
import subprocess
import sys

selector = r"type|isnan|isinfinite|isfinite|isnormal"
result = subprocess.run(
    [sys.executable, "sources/run_conformance.py", "--select", selector, "--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)
summary = report["summary"]
assert sum(summary.values()) > 0
assert summary["fail"] == 0 and summary["error"] == 0
assert result.returncode == 0
=== END AC value-001-type-slice ===

## User Acceptance

- None.

## Guardrails

- The implementation must not invoke an external jq implementation.
- Special numeric values must not cause invalid process output or uncontrolled termination.

=== BEGIN ARTIFACT FEATURE-VALUE-002.md ===
# FEATURE: jq Field and Index Access

| Field       | Value |
|-------------|-------|
| Version     | 20260822 V1 |
| Description | Defines object-field, array-index, string-key, optional, negative-index, and missing-value access. |
| Depends On  | ARCHITECTURE.md, FEATURE-VALUE-001.md |
| Provides    | field access, index access, optional access, negative indices, missing values |
| Consumes    | ordered generator evaluator, jq value model |

## Questions

- None.

## Intent

Access expressions read objects, arrays, and supported indexed values with jq's null and error behavior. Optional access suppresses invalid-access errors.

## Behavior

- `.field` and quoted field access read object members.
- Array indices support positive and negative integer positions.
- Missing object members and out-of-range reads produce null where jq specifies.
- Optional access suppresses access errors.
- Invalid index types raise runtime errors.

## Programmatic Acceptance

=== AC value-002-access-conformance ===
Intent: The authoritative corpus field and index access cases execute successfully.
Suite: scoped
Requires: executable=python3; scope=test

import json
import os
import subprocess
import sys

selector = r"\.[A-Za-z]|\[[-0-9]"
result = subprocess.run(
    [sys.executable, "sources/run_conformance.py", "--select", selector, "--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)
summary = report["summary"]
assert sum(summary.values()) > 0
assert summary["fail"] == 0
assert summary["error"] == 0
assert result.returncode == 0
=== END AC value-002-access-conformance ===

=== AC value-002-optional-slice ===
Intent: The authoritative corpus optional and chained access cases execute successfully.
Suite: scoped
Requires: executable=python3; scope=test

import json
import os
import subprocess
import sys

selector = r"\?"
result = subprocess.run(
    [sys.executable, "sources/run_conformance.py", "--select", selector, "--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)
summary = report["summary"]
assert sum(summary.values()) > 0
assert summary["fail"] == 0 and summary["error"] == 0
assert result.returncode == 0
=== END AC value-002-optional-slice ===

## User Acceptance

- None.

## Guardrails

- Access behavior must preserve generator ordering and multiplicity.
- Optional access must suppress only the access failure, not unrelated failures.

=== BEGIN ARTIFACT FEATURE-VALUE-003.md ===
# FEATURE: jq Slices and Collection Iteration

| Field       | Value |
|-------------|-------|
| Version     | 20260822 V1 |
| Description | Defines array and string slices plus iteration over arrays and objects. |
| Depends On  | ARCHITECTURE.md, FEATURE-VALUE-002.md |
| Provides    | array slices, string slices, array iteration, object iteration |
| Consumes    | field and index access |

## Questions

- None.

## Intent

Slice and iteration expressions preserve jq's ordered generator model across arrays, objects, and strings, including fractional, negative, omitted, and out-of-range bounds.

## Behavior

- `.[]` emits array elements or object values in order.
- `.[start:end]` slices arrays and strings.
- Omitted, negative, fractional, NaN, and out-of-range bounds follow jq rules.
- Optional iteration suppresses errors on non-iterable inputs.
- Empty collections produce empty streams.

## Programmatic Acceptance

=== AC value-003-slice-conformance ===
Intent: The authoritative corpus slice and iteration cases execute successfully.
Suite: scoped
Requires: executable=python3; scope=test

import json
import os
import subprocess
import sys

selector = r"\[.*:|\.\[\]"
result = subprocess.run(
    [sys.executable, "sources/run_conformance.py", "--select", selector, "--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)
summary = report["summary"]
assert sum(summary.values()) > 0
assert summary["fail"] == 0
assert summary["error"] == 0
assert result.returncode == 0
=== END AC value-003-slice-conformance ===

=== AC value-003-iteration-slice ===
Intent: The authoritative corpus array and object iteration cases execute successfully.
Suite: scoped
Requires: executable=python3; scope=test

import json
import os
import subprocess
import sys

selector = r"\.\[\]|\[\.\]"
result = subprocess.run(
    [sys.executable, "sources/run_conformance.py", "--select", selector, "--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)
summary = report["summary"]
assert sum(summary.values()) > 0
assert summary["fail"] == 0 and summary["error"] == 0
assert result.returncode == 0
=== END AC value-003-iteration-slice ===

## User Acceptance

- None.

## Guardrails

- Iteration must preserve output order and multiplicity.
- Optional iteration must not turn valid empty streams into null outputs.

=== END ARTIFACT ===