The Six Term Manipulation Packages

There are currently six library packages that extend Prolog's built-in set of operations on terms. They are

library(arg)

some generalizations of arg/3

library(changearg)

some operations for building new terms

library(occurs)

testing whether a given term does or does not contain another term or variable

library(samefunctor)

some generalizations of functor/3

library(subsumes)

testing whether one term subsumes another

library(unify)

sound unification