unconst (object -- mutableView)

Inputs

• object: Current stack object whose view may become mutable.

Outputs

• mutableView: Resulting stack object in mutable view where valid.

unconst is a current stack-object mutable-view conversion builtin. It converts the current stack object to a mutable view where valid.

For Ref inputs, only the current stack object changes. The referenced storage and any other references remain unchanged.

Behavior

• An immutable Ref input becomes the corresponding mutable Ref to the same target.
• A mutable Ref input is returned unchanged.
• NAME on a non-static, non-callable In-place local is valid because that form produces an immutable Ref view; see selection. unconst returns the mutable view to the same target.
• Code and Text inputs are returned unchanged, including callable non-NIL Code inputs.
• Meta inputs are returned unchanged and still report FALSE under isConst.
• In-place inputs are invalid.

Example

{} 0 {} [
  value: 7;
  codeLocal: {} () {} codeRef;
  unknownText: 0 ("") dynamic @; # an unknown Text
  [] !codeLocal # a non-NIL Code

  "-- current Ref view only --" printCompilerMessage
  value printStack _:;
  value unconst printStack _:;
  value printStack _:;
  @value printStack _:;
  @value unconst printStack _:;
  value isConst printStack _:;
  value unconst isConst printStack _:;
  @value unconst isConst printStack _:;

  "-- accepted non-Ref inputs are unchanged --" printCompilerMessage
  "hi" unconst printStack _:;
  unknownText unconst isConst printStack _:;
  {} () {} codeRef unconst isConst printStack _:;
  @codeLocal unconst isConst printStack _:;
  () unconst isConst printStack _:;

  0
] "main" exportFunction

Expected Output During Compilation

-- current Ref view only --
7 Cref
7 Ref
7 Cref
7 Ref
7 Ref
TRUE
FALSE
FALSE
-- accepted non-Ref inputs are unchanged --
"hi"
TRUE
TRUE
TRUE
FALSE

See also

• const builtin (object -- immutableView) Immutable view conversion for the current stack object.
• fieldIsRef builtin (schema ordinal -- isRefLike) Ref-like test for one selected item schema.
• isConst builtin (object -- isConst) Current stack-object immutability test.
• isRef builtin (object -- object isRefLike) Current stack-object Ref-like predicate.
• managed? builtin (schema -- isManaged) Managed-lifetime schema test.