Cut

The cut operator (!/0) -- currently registered as a plain rule with no body override, which means its body defaults to RuleWrapper's true: ! succeeds without pruning any choice point or alternative branch. :solve-concurrent has no choice-point stack to prune in the first place (see it.unibo.tuprolog.solve.concurrent.fsm.StateRuleSelection's "Cut caveat"), so this is currently a placeholder rather than an ISO-conformant cut -- a comment on this object's registration in it.unibo.tuprolog.solve.concurrent.stdlib.DefaultBuiltins notes it may need converting into a primitive ("smarter behaviour") in the future.