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subcall(+Goal, -Delayed_goals)
Succeeds iff Goal succeeds and unifies Delayed_goals with a list of
remaining delayed goals.
- Goal
- Atom or compound term.
- Delayed_goals
- Variable or list.
Description
   Calls the goal Goal.  When Goal succeeds, Delayed_goals is unified with
   a list of goals that were delayed, but not resumed during execution of
   Goal.  These goals, together with the variable bindings in Goal, can be
   regarded as a qualified answer to Goal.  I.e. Goal is true under the
   condition that the conjunction of delayed goals is also true.
   Note that, after exiting from subcall/2, the goals collected in
   Delayed_goals do no longer exist as delayed goals.
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 neither an atom nor a compound term.
- (68) calling an undefined procedure 
- Goal is an undefined procedure.
Examples
Success:
    [eclipse]: X > 0, subcall(X < 5, DG).
    X = X
    DG = [X < 5]
    Delayed goals:
    X > 0
    yes.
    [eclipse]: subcall( (X > 0, Y > 0, X = 3) , DG).
    Y = Y
    X = 3
    DG = [Y > 0]
    yes.
Fail:
    subcall(fail, _).
Error:
    subcall(Var, D).                (Error 4).
    subcall(3, D).                  (Error 5).
    subcall(foo(a), D).             (Error 68).
See Also
call / 1, @ / 2, : / 2, call_priority / 2