When I used Prolog at university, we built really cool constraint solvers using hardcoded predicates, but is it possible to create the predicates dynamically? T

When I used Prolog at university, we built really cool constraint solvers using hardcoded predicates, but is it possible to create the predicates dynamically? To be useful, if a user has a GUI where they can define rules, they've got to be loaded into the program somehow... hopefully not through code generation?