feat(gfql): Enable Let bindings to accept matchers (ASTNode/ASTEdge)

[lmeyerov]

Summary

Let bindings now accept ASTNode/ASTEdge matchers directly. Implements FILTER semantics (not marking).

Key Changes

1. Direct Matcher Support

• ASTLet accepts ASTNode/ASTEdge without Chain wrapper
• Auto-converts list syntax to Chain in ASTLet.__init__
• Cleaner, more intuitive syntax

2. Filter Semantics

• CRITICAL: Implements FILTER semantics, NOT marking/mask semantics
• n() filters to just nodes (no edges)
• e_forward() filters edges and connected nodes
• Each binding operates on root graph independently (unless using ref())

3. Simplified Implementation

• ASTNode/ASTEdge delegate to chain_impl() for consistent behavior
• Fixed test expectations to match filter semantics
• All 352 compute tests pass

4. Host-Level Dev Scripts

• ./bin/pytest.sh - Runs tests with highest available Python (3.8-3.14)
• ./bin/mypy.sh - Type checking without Docker
• ./bin/flake8.sh - Linting without Docker
• Purpose: Fast local testing without Docker overhead or hardcoded system Python
• Auto-installs tools if missing, uses repo root, proper exit codes

Syntax

# Before: Required Chain wrapper
g.gfql(let({
    'persons': Chain([n({'type': 'person'})])
}))

# After: Direct matchers
g.gfql(let({
    'persons': n({'type': 'person'}),           # Filter nodes
    'adults': ref('persons', [n({'age': ge(18)})]),  # Chain from persons
    'knows': e_forward({'type': 'knows'})       # Filter edges from root
}))

Important Behavior

• n() returns nodes only (edges removed)
• Bindings execute in topological order
• Last executed binding is returned (unless output specified)
• Independent bindings operate on root graph, not accumulated results

Tests

✅ All 352 compute tests pass
✅ No mypy errors
✅ No flake8 errors

[lmeyerov]

dict is too untyped

[lmeyerov]

Super suspicious of wrong semantics.

[lmeyerov]

Super suspicious