Source : Free On-Line Dictionary of Computing

Algebraic Logic Functional language
     
         (ALF) A language by Rudolf Opalla
         which combines
        {functional programming} and {logic programming} techniques.
     
        ALF is based on {Horn clause} logic with equality which
        consists of {predicate}s and Horn clauses for {logic
        programming}, and functions and equations for {functional
        programming}.  Any functional expression can be used in a
        {goal} literal and arbitrary predicates can occur in
        conditions of equations.  ALF uses {narrowing} and
        {rewriting}.
     
        ALF includes a compiler to {Warren Abstract Machine} code and
        {run-time support}.
     
        {(ftp://ftp.germany.eu.net/pub/programming/languages/LogicFunctional)}.
     
        ["The Implementation of the Functional-Logic Language ALF",
        M. Hanus and A. Schwab].
     
        (1992-10-08)