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call(+Goal)

Succeeds if Goal succeeds.
Goal
Atom or compound term.

Description

Calls the goal Goal. This predicate is used to call goals whose functors are known only at the time they are called.

Note that:

call(Goal) is logically the same as Goal and !/0 does not cut through call/1.

Modules

This predicate is sensitive to its module context (tool predicate, see @/2).

Fail Conditions

Fails if Goal fails

Resatisfiable

Resatisfiable if Goal is resatisfiable

Exceptions

(4) instantiation fault
Goal is not instantiated.
(5) type error
Goal is not an atom or a compound term.

Examples

Success:
      [eclipse]: [user].
       or(A -> B, C) :- call(A), !, call(B).
       or(_ -> _, C) :- call(C).
       user compiled 412 bytes in 0.02 seconds
      [eclipse]: or(write(a)->fail, write(k)).
      a
      no.
      [eclipse]: or(fail->write(here),true).
      yes.

Fail:
      [eclipse]: call(fail),write(here).
      no.
Error:
      call(G).                  (Error 4).
      call("write(a)").         (Error 5).



See Also

subcall / 2, @ / 2, : / 2