Optional and Owning Values

The std module provides optional#T for an inline value that may be absent, and unique_ptr#T for ownership of one allocated object.

Optional values

IMPORT std;

::optional_example FUNCTION(): I32
{
  VAR number std::optional#I32 := NULL;
  TEST_ASSERT(number!?);
  number.emplace(@OTHER 42);
  TEST_ASSERT(number??);
  VAR result I32 := number->;
  number := NULL;
  RETURN result;
}

has_value() and postfix ?? test engagement; !? negates that test. value() and postfix -> access the contained value and require engagement. reset() destroys it. emplace(...) forwards constructor arguments. Moving an optional leaves its source engaged with a moved-from value.

Owning pointers

IMPORT std;

::ownership_example FUNCTION(): I32
{
  VAR first AUTO := std::make_unique#I32(@OTHER 42);
  VAR second std::unique_ptr#I32 := MOVE(first);
  TEST_ASSERT(first!?);
  RETURN second->;
}

A move transfers ownership and empties the source. Destruction deletes the owned object. get() borrows the raw pointer; release() transfers deletion responsibility to the caller. Both types support value->.field when their contained object has fields.

See the reference for access, construction, and ownership requirements.