| succeeds always.
repeat
repeat/0 succeeds repeatedly and indefinitely. The difference
to true/0 is that it can be backtracked.
Loops which are defined with repeat/0 should be finished with
a Cut ('!'/0), because otherwise the loop can be repeated.
If a predicate, called after repeat/0, always fails, you can have
an indefinite loop. If repeat/0 follows after a conjunction
(','/2) the part left of it won't be backtraced any more.
Examples
| repeat, write('indefinitely'), nl, fail. |
Writes indefinitely 'indefinitely' to the current outputstream. |
| repeat,!.
| Succeeds. |
| repeat,!,fail. |
Fails. |
Standard
This predicate is part of the ISO-Prolog Standard.
See also
abort/0,
break/0,
call/1,
fcall/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,
once/1,
throw/1.
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