a_owner.chr

:- module(owner, [classify/1, run/2]).

% Open class: extension directives are allowed to appear interleaved
% with the original decls and equations.
:- open_class (classify(int) -> int).

% An extend_class_type directive between the open_class decl and
% the first equation is permitted (extensions are not subject to the
% decl-contiguity rule).
:- extend_class_type (classify(int) -> int).

classify(0) -> 100.

% An extend_class directive between equations is also permitted.
:- extend_class classify(1) -> 101.

:- chr_constraint run/2.
run(X, R) <=> R is classify(X).