A Prolog library (primary for Scryer Prolog) that aims to generalize common Prolog predicates using constaints so that they are more flexible and declarative.
Currently offers functor_c/3, #=../2 and length_c/2, which are constraint
versions of functor/3, =../2 and length/2 respectively. They work in all
directions, including the most general case where all arguments are variables, ensure consistency, and delay the instantiation of their arguments. Reified versions of these predicates are also provided for use with library(reif).