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+P ,
+Q
+P ;
+Q
\+
+Guard
+Guard ->
+Q ;
+R
+Q is called for every possible solutions of Guard.
+R is only called if Guard has no solutions.
+Guard ->
+Q
+Guard ->
+Q;fail
true
fail
wait(
+Goal)
The library call
provide the additionnal predicate:
call(
Goal)
call(
Term)
is executed
exactly as if that term appeared textually in its place. There are some
restrictions on Goal.