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+Goal1 ; +Goal2

Semicolon (OR) operator - Succeeds if the goal Goal1 succeeds or if the goal Goal2 succeeds.

Goal1: Atom or compound term.
Goal2: Atom or compound term.

Description

Succeeds if either of Goal1 and Goal2 succeeds.

If Goal1 has the special form A -> B (or A *-> B) then the disjunction turns into an if-then-else construct. See those predicates for details.

!/0 cuts through ;/2.

Modes and Determinism

;(+, +) is nondet

Modules

This predicate is sensitive to its module context (tool predicate, see @/2).

Fail Conditions

Fails if both Goal1 and Goal2 fail

Resatisfiable

Resatisfiable if Goal1 does not contain a literal cut

Examples

Success:
      1 == 2; 2 == 2.

      [eclipse]: (write(a), fail) ; (write(b); write(c)).
      ab
      yes.

      [eclipse]: (write(a); write(b)), write(c).
      ac
      yes.

Fail:
      1 == 2; 3 == 2.