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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.
| document: http://www.ifcomputer.co.jp/MINERVA/Manual/Reference/Predicates/logic_and_control/repeat/print_en.html published 2008/10/13 update 2001/2/7 (c) 1996-2006 IF Computer Japan | ||||||||
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