
constraints(+SpecList)

   Directive for declaring SpecList to be CHR constraints

Arguments
   SpecList            Sequence of the form Atom/Integer

Type
   library(ech)

Description
   Declares the predicates specified in SpecList as CHR constraints. This 
   allows the predicate to appear in the head of a CHR rule.


   Note that a predicate declared as a CHR constraint should not appear as
   a normal ECLiPSe predicate. Any such definition of the predicate in the
   user's program would be replaced by the CHR definition.


Examples
      :- constraints leq/2.
   :- op(700, xfx, leq).

   X leq Y <=> \+nonground(X), \+nonground(Y) | X @=< Y.
   X leq X <=> true.



