True if Term represents a function from In to Out
implemented by calling Goal. This multifile hook is
called by $/2 and of/2 to convert a term into a goal.
It's used at compile time for macro expansion.
It's used at run time to handle functions which aren't
known at compile time.
When called as a hook, Term is guaranteed to be
For example, to treat library(assoc) terms as functions which
map a key to a value, one might define:
:- multifile compile_function/4.
compile_function(Assoc, Key, Value, Goal) :-
Goal = get_assoc(Key, Assoc, Value).
Then one could write:
list_to_assoc([a-1, b-2, c-3], Assoc),
Two = Assoc $ b,
Apply Function to an Argument. A Function is any predicate
whose final argument generates output and whose penultimate argument
This is realized by expanding function application to chained
predicate calls at compile time. Function application itself can
Reversed = reverse $ sort $ [c,d,b].
Creates a new function by composing F and G. The functions are
composed at compile time to create a new, compiled predicate which
behaves like a function. Function composition can be chained.
Composed functions can also be applied with $/2.
Reversed = reverse of sort $ [c,d,b].