adding-swifql-sql-function

name	adding-swifql-sql-function
description	Add or change a built-in compositional SQL function helper inside the SwifQL repository. Use for contributor work in SwifQL source, not for downstream custom functions in consuming apps or packages.

Add a Compositional SQL Function

Use this procedure when adding a compositional SQL function helper. Architecture and value-safety authority remain DSL_COMPOSITION.md and SAFETY_RULES.md.

1. Load DSL_COMPOSITION.md, SAFETY_RULES.md, and SOURCE_MAP.md.
2. Inspect neighboring current files under Sources/SwifQL/Functions/** and the current Fn construction before choosing the helper shape.
3. Classify each argument as SQL structure or dynamic data.
4. Prefer composition of existing parts and current Fn helpers.
5. Keep dynamic data on the normal bound-value path; use trusted inline representation only for deliberately controlled structure.
6. Add dialect-specific expectations only where semantics or rendering actually differ.
7. Avoid opportunistic renaming or refactoring of historical function APIs and unrelated helpers.