5.6.3 SSU: Future considerations

The current implementation is a rather simple. Single sided unification is achieved doing normal head unification and backtrack if this unification bound variables in the goal term. Future versions are likely to backtrack as soon as we find a variable in the goal that needs to be unified.

It is likely that in due time significant parts of the libraries will be migrated to use SSU rules, turning many silent failures on type errors into errors.