fieldCount (schema -- itemCount)

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.

fieldCount (schema -- itemCount)

Inputs

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

Outputs

itemCount: Known Int32 count of items in the Struct schema.

Returns the number of items in the dereferenced Struct schema as a known Int32 value. Only the schema participates. Current value contents do not participate.

Duplicate names, unnamed items, static items, and Meta items all count separately. The result therefore counts schema items, not unique names and not runtime storage slots.

The valid selected-item ordinal range of the dereferenced schema is 0 through itemCount - 1.

Behavior

Ref values are dereferenced before counting, so a Ref to a Struct produces the same result as the referenced schema.

For Dict, every schema item counts, including duplicate names, unnamed items, static items, and Meta items.

For List and Tuple, each item counts once in ordinal order.

The empty Tuple has count 0.

The result is always known Int32.

Example

{} 0 {} [ dict: { x: 1; virtual y: 2; z: (); x: 3; }; "-- duplicate names still count separately --" printCompilerMessage dict fieldCount printStack _:; dict 0 fieldName printStack _:; dict 1 fieldName printStack _:; dict 2 fieldName printStack _:; dict 3 fieldName printStack _:; "-- Ref to Dict --" printCompilerMessage @dict fieldCount printStack _:; "-- List --" printCompilerMessage (1 2 3) fieldCount printStack _:; "-- Tuple --" printCompilerMessage (1 FALSE) fieldCount printStack _:; "-- empty Tuple --" printCompilerMessage () fieldCount printStack _:; 0 ] "main" exportFunction

Expected Output During Compilation

-- duplicate names still count separately -- 4 "x" "y" "z" "x" -- Ref to Dict -- 4 -- List -- 3 -- Tuple -- 2 -- empty Tuple -- 0