Previous Up Next

7.3  User-Defined Constraints

7.3.1  Generalised Propagation: propia

The predicate infers takes as one argument any user-defined predicate, and as a second argument a form of propagation to be applied to that predicate.

This functionality enables the user to turn any predicate into a constraint [
14]. The forms of propagation include finite domains and intervals. For more details see chapter 15.

7.3.2  Constraint Handling Rules: ech

The user can also specify predicates using rules with guards [9]. They delay until the guard is entailed or disentailed, and then execute or terminate accordingly.

This functionality enables the user to implement constraints in a way that is clearer than directly using the underlying suspend library. For more details see chapter
15.


Previous Up Next