ALF
Foundation: Horn clause logic with equality which consists of predicates and Horn clauses for logic programming, and functions and equations for functional programming. A full integration of both programming models, so any functional expression can be used in a goal literal and arbitrary predicates can occur in conditions of equations.
url: www.informatik.uni-kiel.de/~mh/systems/ALF.html
BABEL
Operational semantics based on lazy narrowing; provides some higher-order features.
url: www-i2.informatik.rwth-aachen.de/Research/BABEL/
Curry
Multiparadigm declarative programming language seamlessly merges functional, logic, and concurrent programming paradigms; covers the most important operational principles in the area of integrated functional logic languages.
url: www.informatik.uni-kiel.de/~curry/
Escher
Declarative, general-purpose language, merges best features of functional and logic languages. Has types and modules, higher-order and meta-programming facilities, declarative input/output. Set of system modules provides many operations on standard data types: integers, lists, characters, strings, sets, programs.
url: www.cs.bris.ac.uk/~jwl/escher.html
Functional Logic Programming
Michael Hanus's pages on amalgamating functional and logic programming.
url: www.informatik.uni-kiel.de/~mh/FLP/
RELFUN
Relational-Functional Language: logic-programming language with call-by-value (eager) expressions of non-deterministic, non-ground functions; clauses are Hornish, succeeding with true(s), or footed, returning any value(s), and define operations (relations, functions) allowing (apply-reducible) higher-order syntax with arbitrary terms (constants, structures, variables) as operators.
url: www.dfki.uni-kl.de/~vega/relfun.html
