:Condition/0¶

0:Condition* -> 0:Action is iso

If Condition has a solution, call _Action__;

@long Read as "if-then-else" or "commit". This operator is similar to the conditional operator of imperative languages and can be used alone or with an else part as follows:

 +P -> +Q

"if P then Q".

 +P -> +Q; +R

"if P then Q else R".

These two predicates could be defined respectively in Prolog as:

 (P -> Q) :- P, !, Q.

and

 (P -> Q; R) :- P, !, Q.
 (P -> Q; R) :- R.

if there were no "cuts" in P, Q and R.

vNote that the commit operator works by "cutting" any alternative solutions of P.

Note also that you can use chains of commit operators like:

 P -> Q ; R -> S ; T.

Note that (->)//22 does not affect the scope of cuts in its arguments.