add-tsl-primitive

name	add-tsl-primitive
description	Add or update a TSL primitive in tsldata and the tslc compiler. Use when asked to add a new primitive, change primitive signatures/tests/bodies, support a new primitive shape, or make primitive source data compile through parsing, validation, selection, lowering, rendering, and generated value tests.

Add TSL Primitive

Workflow

1. Read AGENTS.md, CHARTER.md, PLANS.md, tsldata/AGENTS.md, tslc/AGENTS.md, tslc/CHARTER.md, and the closest existing primitive examples under tsldata/primitives/.
2. Identify the primitive family, signatures, type groups, extension coverage, masks, immediate parameters, and value-test needs before editing.
3. Add or update source data in tsldata/ first. Keep source forms explicit; do not make the compiler silently repair malformed .tsl.
4. If the current parser/catalog/schema does not accept the needed shape, add typed validation and promotion at the parser/catalog boundary.
5. If selection or lowering needs new behavior, add typed domain/lowering values. Avoid raw string rewrites and avoid leaking dictionaries past catalog boundaries.
6. If rendering or value tests need support, add backend capability checks before render-time surprises.
7. Add focused tests at the touched boundary, then broaden to generated-output or value-test coverage when behavior crosses lowering/rendering.

Checks

• Verify diagnostics for malformed or unsupported nearby source forms.
• Verify deterministic ordering for any added source traversal, selected slots, artifacts, or diagnostics.
• Verify extension-point behavior: the next similar primitive should not require edits in unrelated modules.
• Prefer one representative primitive fixture plus corpus coverage when the primitive family affects many existing paths.

Useful Commands

PYTHONPATH=tslc/src python -m pytest -q tslc/tests/test_catalog_validation.py
PYTHONPATH=tslc/src python -m pytest -q tslc/tests/test_select_and_lower*.py tslc/tests/test_lower_text.py
PYTHONPATH=tslc/src python -m pytest -q tslc/tests/test_value_test_planning.py tslc/tests/test_value_tests.py
./dev.sh build --primitives NAME --profiles scalar,avx2 --backends cpp,rust