Core change:
- dbf.KeyEvalFunc: global callback set by gengo before OrderCreate
- evalKeyExprInner default case: calls KeyEvalFunc for unknown functions
- Final fallback: any unresolvable expression → KeyEvalFunc → MacroEval
- valueToKeyBytes: converts MacroEval result to index key bytes
- gengo: sets dbf.KeyEvalFunc = t.MacroEval before OrderCreate, clears after
Examples that now work:
INDEX ON MyFunc(FIELD->NAME) TO idx // UDF in key expression
INDEX ON CityKey(FIELD->CITY, NAME) TO idx // multi-param UDF
INDEX ON Left(MyFunc(NAME), 15) TO idx // nested built-in + UDF
Also fixed:
- SET ORDER TO n: int→string via hbrt.NtoS (was empty string)
- CDX compound leaf decoder: proper bit-packed tag name extraction
- CDX compound recNo = direct byte offset (not page number)
All existing tests pass, NTX 47/47 + CDX 20/20 Harbour compat maintained.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>