isCombined (schema -- isCombined)

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.

isCombined (schema -- isCombined)

Inputs

schema: Value or Ref whose dereferenced schema is tested for the Struct group.

Outputs

isCombined: Known Cond result that is TRUE when schema dereferences to any Struct.

isCombined is a dereferenced-schema predicate. It tests whether the dereferenced schema is any Struct.

In current builtin terminology, combined means Dict, List, or Tuple, including the empty Tuple (). It is a schema-group test, not a field-count or nonempty-container test, and current value contents do not participate.

Behavior

The result is always known.

Dict, List, and Tuple schemas produce TRUE, including the empty Tuple ().

Zero item count does not matter. The empty Tuple still reports TRUE because it is still a Tuple schema.

Ref values are dereferenced before the test, so a Ref to a Struct value also produces TRUE.

All non-Struct schemas produce FALSE.

Example

{} 0 {} [ dict: { x: 1; }; "-- Dict and Ref --" printCompilerMessage dict isCombined printStack _:; @dict isCombined printStack _:; dict fieldCount printStack _:; "-- empty Tuple --" printCompilerMessage () isCombined printStack _:; () fieldCount printStack _:; "-- non-Struct values --" printCompilerMessage 0 isCombined printStack _:; [] isCombined printStack _:; 0 ] "main" exportFunction

Expected Output During Compilation

-- Dict and Ref -- TRUE TRUE 1 -- empty Tuple -- TRUE 0 -- non-Struct values -- FALSE FALSE