FEATURE: Lexical Variable Bindings

Workflow

Bindings evaluate the left-hand filter as a generator, bind each produced value lexically, and run the remainder of the expression with the original input and the active binding environment.

• EXP as $name | REST supports multiple generated bindings.
• Bindings are immutable and lexically scoped.
• Nested bindings may shadow outer names without mutating them.
• Keyword identifiers may be used as binding names.
• Array and object patterns bind missing members as null.

Programmatic Acceptance

=== AC func-001-conformance ===
Intent: The executable passes the authoritative conformance cases exercising lexical bindings and variable lookup.
Suite: scoped
Requires: executable=python3; scope=test

import json import os import subprocess import sys

SELECT = r" as \$|\$[A-Za-z]" 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 func-001-conformance ===

User Acceptance

• Variable values remain available only within their lexical scope and preserve generator backtracking.

Guardrails

• Do not implement bindings as mutable global variables.
• Do not leak nested or out-of-scope bindings.