annotate

[procedure] annotate type rep

If rep's type is the same as type, returns rep.

Otherwise, create a new object of type type whose content is rep. No magical coercion is done; it seems that the caller is fully responsible to make sure rep is a suitable data to be the content of the type.

As of arc0, the only "annotated" objects used in the core arc system are macros. What the mac macro does is this:

(annotate 'mac <transform-fn>)