| succeeds exactly once.
true/0
true/0 succeeds exactly once.
Examples
| write('this is going to succeed'), true. |
Succeeds with output on the current outputstream
'this is going to succeed'.
|
| integer(a),true. |
Fails.
|
Standard
This predicate is part of the ISO-Prolog Standard.
See also
abort/0,
break/0,
fail/0,
call/1,
fcall/1,
catch/3,
','(conjunction)/2,
'!'(cut)/0,
';'(disjunction)/2,
halt/0/1,
'->'(if-then)/2,
';'(if-then-else)/2,
'\+'(not provable)/1,
once/1,
repeat/0,
throw/1.
|
