fieldName (schema ordinal -- itemName)

Builtins

Name introduction, declaration modifiers, and module binding: NAME: ...;, codeRef, def, exportFunction, importFunction, importVariable, overload, private, static, use, and virtual.
Struct construction forms: (...), {...}, and array.
Selection forms: source-text selection with NAME and .NAME, read-only source-text selection with @NAME and .@NAME, and ordinal or known-name data-input selection with @, callField, and fieldRead.
Writing forms: source-text selection with !NAME and .!NAME, ordinal selection with ! and fieldWrite, and already-selected destination replacement with set.
Calling and control flow: call, if, loop, ucall, and uif.
Text operations: &, LF, attribute, textSize, and textSplit.
Condition constants, value comparison, and logical operators: <, =, >, DEBUG, FALSE, TRUE, and, is, lshift, or, rshift, xor, and ~.
Arithmetic and numeric transforms: *, +, -, /, ^, cast, ceil, cos, floor, log, log10, mod, neg, sin, and sqrt.
Reference, creation, and value-state operations: const, dynamic, isConst, isDirty, isDynamic, isRef, isStatic, known?, new, newVarOfTheSameType, stable?, unconst, and unknownStable?.
Schema and struct introspection: code?, codeRef?, fieldCount, fieldIndex, fieldIsRef, fieldIsVirtual, fieldName, has, isCombined, managed?, same, schemaName, and virtual?.
Storage and manual lifetime operations: addressToReference, alignment, manuallyDestroyVariable, manuallyInitVariable, storageAddress, and storageSize.
Diagnostics and compile-time failure: failCompilation, getCallTrace, printCompilerMessage, printStack, printStackTrace, and raiseStaticError.

fieldName (schema ordinal -- itemName)

Inputs

schema: Value or Ref whose dereferenced schema is Struct and whose stored item name is returned.

ordinal: Known zero-based item ordinal whose name is returned.

Outputs

itemName: Known Text name stored at the selected item ordinal.

Returns the stored name for one selected item ordinal in the dereferenced Struct schema. Unnamed items return the empty Text "".

Only the schema participates. Current value contents do not participate.

The ordinal input is dereferenced and must be known at compile time. fieldName preserves the name at the specified ordinal. Repeated names remain repeated and empty names remain empty.

fieldName is therefore not an inverse of fieldIndex when names repeat or are empty, because fieldIndex collapses all matches to the last matching ordinal.

Behavior

The ordinal input must be a known Int32 in the range 0 through itemCount - 1. Out-of-bounds ordinals are invalid.

For Dict, the stored name at that ordinal is returned exactly.

For List and Tuple, every valid ordinal returns "".

Different ordinals may return the same name when names repeat.

Repeated names and empty names remain distinct by ordinal, even though a later name-based selection may collapse them to the last match.

Example

{} 0 {} [ mixed: { 1 "" def 2 "" def 3 "x" def 4 "x" def }; "-- fieldName keeps each ordinal separate --" printCompilerMessage mixed 0 fieldName printStack _:; mixed 1 fieldName printStack _:; mixed 2 fieldName printStack _:; mixed 3 fieldName printStack _:; "-- fieldIndex collapses to the last match --" printCompilerMessage mixed "" fieldIndex printStack _:; mixed "x" fieldIndex printStack _:; "-- Tuple items are unnamed --" printCompilerMessage (1 FALSE) 0 fieldName printStack _:; (1 FALSE) 1 fieldName printStack _:; 0 ] "main" exportFunction

Expected Output During Compilation

-- fieldName keeps each ordinal separate -- "" "" "x" "x" -- fieldIndex collapses to the last match -- 1 3 -- Tuple items are unnamed -- "" ""