FEATURE: Path Access and Mutation Primitives

Purpose

Implement immutable access and mutation of nested arrays and objects through explicit path arrays.

Behavior

• getpath reads values at supplied paths and returns null for absent paths where specified.
• setpath creates missing object and array structure and updates existing values.
• delpaths removes all requested paths without mutating the original input.
• Multiple path expressions preserve their generator order.
• Invalid path types, negative indices, and excessive path depth produce jq runtime errors or no-ops according to the specification.

Programmatic Acceptance

=== AC path-002-conformance ===
Intent: The authoritative corpus slice covering getpath, setpath, and delpaths executes and passes.
Suite: scoped
Requires: executable=python3; scope=test

import json import os import subprocess import sys

select = r"getpath|setpath|delpaths" 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) summary = report["summary"] assert sum(summary.values()) > 0 assert summary["fail"] == 0 assert summary["error"] == 0 assert result.returncode == 0 === END AC path-002-conformance ===

User Acceptance

• None.

Guardrails

• Values remain immutable from the filter author's perspective.
• Do not treat invalid paths as valid object keys or array indices.
• Enforce the supplied depth and indexing semantics.