Significant internal restructuring of the unification algorithm. Bindings which are already known to be consistent are no longer rechecked, giving a significant speedup.
Added utility functions for the restructured Unification algorithm.
Old, uncommitted additions to Datatypes.sml
Added a 'print' built-in predicate. Added a function for removing bindings of a particular scope.
Fixed a bug where previous unification bindings were not correctly applied in subsequent bindings.
Fixed a bug where underscores in predicate names were not parsed correctly.