ALF

Appeared in Volume 6/1, February 1993

Keywords: functions.

ALF (Algebraic Logic Functional programming language) combines functional and logic programming techniques. The foundation of ALF is Horn clause logic with equality which consists of predicates and Horn clauses for LP, and functions and equations for functional programming. Since ALF is an integration of both programming paradigms, any functional expression can be used in a goal literal and arbitrary predicates can occur in conditions of equations.

The abstract machine is based on the Warren Abstract Machine (WAM) with several extensions to implement narrowing and rewriting. In the current implementation programs of this abstract machine are executed by an emulator written in C.

You can find ALF in the path /pub/programming/languages/LogicFunctional.
There are three files which contain:

1. alf_sys.zoo:

Documentation
C sources (for the emulator) - should work with all 16/32 bit-systems
Compiled version of the preprocessor (see below)
Compiled version of the compiler
some basic modules
small examples

2. alf_pp.zoo:

ALF sources for the preprocessor (type-checking, manages a module-concept, etc)

3. alf_comp.zoo:

ALF sources for the compiler, which translates the preprocessors output into:

a file which is executable through the emulator
WAM-like instructions (text)

For more information contact:

Rudolf Opalla
Email: opalla@owl.informatik.uni-dortmund.de