FEATURE: Deletion and Assignment Operators

Purpose

Implement jq's immutable deletion, plain assignment, update assignment, and arithmetic assignment semantics.

Behavior

• del removes values selected by one or more path expressions.
• Plain assignment evaluates the right-hand side against the original input and uses every produced value.
• Update assignment evaluates the right-hand side against each selected value and uses the first result.
• Arithmetic assignments apply the corresponding operator to selected values.
• Defined-or assignment replaces false or null values with the right-hand result.
• Multi-path assignments preserve jq's output ordering and multiplicity.

Programmatic Acceptance

=== AC path-003-conformance ===
Intent: The authoritative corpus slice covering deletion and assignment operators executes and passes.
Suite: scoped
Requires: executable=python3; scope=test

import json import os import subprocess import sys

select = r"=|\|=|\+=" 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-003-conformance ===

User Acceptance

• None.

Guardrails

• Assignment must produce immutable values and must not leak mutations between outputs.
• Preserve the distinction between = and |=.
• Empty update streams delete the selected path.