This simple module implements the directive coinductive/1 as described
in "Co-Logic Programming: Extending Logic Programming with Coinduction"
by Luke Simon et al. The idea behind coinduction is that a goal succeeds
if it unifies to a parent goal. This enables some interesting programs,
notably on infinite trees (cyclic terms).
:- coinductive p/1.
p([1|T]) :- p(T).
This predicate is true for any cyclic list containing only 1-s,
regardless of the cycle-length.
- See also
- - "Co-Logic Programming: Extending Logic Programming with Coinduction"
by Luke Simon et al.
- - Programs mixing normal predicates and coinductive predicates must
be stratified. The theory does not apply to normal Prolog calling
coinductive predicates, calling normal Prolog predicates, etc.
Stratification is not checked or enforced in any other way and thus
left as a responsibility to the user.
- head(+Term, -QHead) is semidet[private]
- Must be first to allow reloading!
- The declaration :- coinductive name/arity, ... defines
predicates as coinductive. The predicate definition is wrapped
such that goals unify with their ancestors. This directive must
precede all clauses of the predicate.
- wrap_coinductive(+Head, +Term, -Clauses) is det[private]
- Create a wrapper. The first clause deal with the case where we
already created the wrapper. The second creates the wrapper and
the first clause.
- rename_clause(+Clause, +Prefix, -Renamed) is det[private]
- Rename a clause by prefixing its old name wit h Prefix.