set (source destination --)

Inputs

• source: Source object assigned to destination.
• destination: Already-selected destination object or Ref to the destination.

Outputs

• None.

set replaces an already-selected mutable same-schema destination after dereferencing both inputs. No selection happens inside the builtin.

set is the final replacement step after a separate selection form such as @NAME, .@NAME, @, or fieldRead. After dereferencing, source mutability decides whether the source is copied or moved. A Ref source differs from a direct value only by that source mutability.

set replaces the selected destination object itself. If destination is a Ref, the object reached through that Ref is replaced; the stored Ref object is not changed. Replacing a stored Ref object instead requires a combined selection-and-write form such as ! or fieldWrite.

Behavior

• An immutable object and a mutable same-schema destination produce a copy. The original value keeps its contents.
• A mutable object and a mutable same-schema destination produce a move. The original mutable object no longer keeps its previous contents.
• An immutable destination is invalid.
• Different dereferenced schemas are invalid.
• Text destinations are invalid.
• Code destinations are invalid.

Example

"Owner"  use
"String" use

{} () {} [
  copySource: 7;
  copyTarget: 0;
  copySource @copyTarget set
  ("-- immutable value path copies -- " copySource " " copyTarget "\n") printList

  moveSource: 5 owner;
  moveTarget: 0 owner;
  @moveSource @moveTarget set
  ("-- mutable value path moves -- " moveSource.valid? " " moveTarget.valid? "\n") printList
] "main" exportFunction

Expected Output

-- immutable value path copies -- 7 7
-- mutable value path moves -- FALSE TRUE

See also

• @NAME node @NAME Named local or visible-field read that can supply a selected destination for set.
• .@NAME node .@NAME Named field read on a popped Dict that can supply a selected destination for set.
• @ builtin (ordinal structValue -- selectedItem) Ordinal-based data-input selection and read with the ordinal before the Struct object.
• fieldRead builtin (structValue ordinal -- selectedItem) Ordinal-based data-input selection and read with the Struct object before the ordinal.
• !NAME node !NAME Direct named write when selection and replacement are combined in one source form.
• .!NAME node .!NAME Direct named field write on a popped mutable Dict when selection and replacement are combined.
• ! builtin (source ordinal structTarget --) Ordinal-based data-input selection and write with the ordinal before the Struct target.
• fieldWrite builtin (source structTarget ordinal --) Ordinal-based data-input selection and write with the Struct target before the ordinal.