|
|
|
|
|
|
|
|
Goedel Version 1.3Appeared in Volume 6/4, November 1993
Goedel is a declarative, general-purpose programming language in the family of logic programming languages. It is a strongly typed language, the type system being based on many-sorted logic with parametric polymorphism. It has a module system. Goedel supports infinite precision integers, infinite precision rationals, and also floating-point numbers. It can solve constraints over finite domains of integers and also linear rational constraints. It supports processing of finite sets. It also has a flexible computation rule and a pruning operator which generalises the commit of the concurrent logic programming languages. Considerable emphasis is placed on Goedel's meta- logical facilities which provide significant support for meta-programs that do analysis, transformation, compilation, verification, debugging, and so on.
This release contains:
Goedel should be of particular interest to four groups:
(a) Those doing research in program transformation, program analysis, debugging, and a wide range of other meta-programming tasks. Goedel provides significant advantages for such tasks since it is much more declarative than Prolog, for example, and also a great deal of effort has been put into providing special support for meta-programming. Goedel makes possible advanced software engineering tools such as declarative debuggers and compiler generators.
(b) Those doing research in parallel implementations of logic programming languages. The declarative nature of Goedel greatly eases the task of building a parallel implementation of the language (compared to Prolog, for example, whose non-logical facilities cause serious difficulties for parallel implementations) and offers substantial scope for parallelization in such implementations.
(c) Those teaching logic programming. Goedel fits much better than Prolog, for example, into the undergraduate and graduate curricula since it has a type and module system similar to other commonly used teaching langauges such as Miranda and Modula-2. Also most of the problematical non-logical predicates of Prolog simply aren't present in Goedel (they are replaced by declarative counterparts) and so the cause of much confusion and difficulty is avoided.
(d) Those working in the theory of logic programming. There has always been a large gap between the theory of logic programming (as in "Foundations of Logic Programming", for example) and the much more complex and unsatisfactory semantics of practical logic programming languages, such as Prolog. Goedel significantly narrows this semantic gap. This means that theoreticians can apply their "pure" theories of program transformation, program analysis, etc., more or less directly to Goedel and do not have to be concerned with complications of extending their theories to cope with the many non-logical aspects of languages such as Prolog.
This release provides a (substantial) subset of the language. The remainder of the implementation is expected to be completed over the next year or so.
SICStus Prolog version 2.1 #6 (or later) is required to compile the Goedel system. As an alternative for those who do not have SICStus Prolog, a run-time system is provided which gives a version that runs on a SPARCstation.
The system is available by anonymous FTP. The FTP sites are:
ftp://ftp.cs.kuleuven.ac.be/pub/logic-prgm/goedel/ (134.58.41.2)
ftp://ftp.cs.bris.ac.uk/goedel (137.222.102.102).
Please register when you obtain the system, by sending a message consisting of
your name, institution, and address to:
goedel@compsci.bristol.ac.uk
|
|
|
|
|
|
|
|