term_expansion(Term, Expansion)
Defines an expansion for a term. This predicate, when defined, is automatically called by the expand_term/2
method. Use of this predicate by the expand_term/2
method may be restricted by changing its default public scope. The term_expansion/2
clauses are only used by the expand_term/2
method if they are within the scope of the sender. When that is not the case, the expand_term/2
method only uses the default expansions. The term_expansion/2
predicate may return a list of terms.
Term expansion may be also be applied when compiling source files by defining the object providing access to the term_expansion/2
clauses as a hook object. Clauses for the term_expansion/2
predicate defined within an object or a category are never used in the compilation of the object or the category itself. Moreover, terms wrapped using the {}/1
compiler bypass control construct are not expanded and any expanded term wrapped in this control construct will not be further expanded.
Objects and categories implementing this predicate should declare that they implement the expanding
protocol. This protocol implementation relation can be declared as either protected or private to restrict the scope of this predicate.
term_expansion(+nonvar, -nonvar) term_expansion(+nonvar, -list(nonvar))
(none)
term_expansion((:- license(default)), (:- license(gplv3))).
term_expansion(data(Millimeters), data(Meters)) :- Meters is Millimeters / 1000.