Other logic-related languages of interest.

lang/prolog/impl/other/

   goedel/    Goedel: Prolog-like language with improved 
              declarative semantics.
   ho_unif/   HO_UNIF: Higher Order E-Unification
   prosit/    PROSIT: Programming in SItuation Theory
   sel2/      SEL2: Declarative set-processing language that 
              generates WAM code