The archetypal application needs
a value object (or valuator) to produce
the value of the parse.
To create a valuator, use the
When a valuator is no longer in use, its memory can be freed
The application is required to maintain the stack,
and the application is also required to implement
most of the semantics, including the evaluation
Libmarpa’s valuator provides instructions to
the application on how to manipulate the stack.
To iterate through this series of instructions,
marpa_v_step() returns the type
Most step types have values associated with them.
To access these values use the methods
described in the section Basic step accessors.
How to perform the steps is described in
How to use the valuator
and Stepping through the valuator.