| Executes a goal only once and throws an exception if the goal fails.
fcall(?Goal)
fcall/1 works like once/1, but throws an exception
if the execution of Goal fails.
Arguments
Goal goal
Examples
| fcall((member(X,[a,b,c]))). |
Succeeds only once with substitution X <- a. |
| fcall((member(d,[a,b,c]))). |
throws an exception. |
Standard
This predicate is not part of the ISO-Prolog Standard.
See also
abort/0,
break/0,
call/1,
catch/3,
','(conjunction)/2,
'!'(cut)/0,
';'(disjunction)/2,
fail/0,
true/0,
halt/0/1,
'->'(if-then)/2,
';'(if-then-else)/2,
'\+'(not provable)/1,
repeat/0,
throw/1.
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