jws@mulga.oz (Jeff Schultz) (06/06/88)
Version 1.3 of the NU-Prolog system is now available for release to academic institutions (schools, colleges, universities). Commercial licences are also available for some machines. This release includes a much improved interpreter and debugger, both of which now understand when declarations; floating point arithmetic; an interface to foreign functions on many machines; and the usual large collection of bug fixes. Performance has been increased by 10 to 20 per cent for many applications. NU-Prolog is a second generation Prolog system which incorporates a number of important advances in Logic Programming implementation. NU-Prolog was implemented as part of the Machine Intelligence Project+ in the Department of Computer Science at the University of Melbourne. It is the successor to Lee Naish's successful MU-Prolog system and attempts to move Prolog closer to the ideals of Logic Programming by allowing the user to program in a style closer to first order logic. In addition, it provides substantial performance gains over interpreted systems such as MU-Prolog. NU-Prolog has the following features: * compiles Prolog programs into machine code for an enhanced version of the Warren abstract machine (implementing the delay/coroutine style of programming of MU-Prolog) * incorporates a database system based on superimposed codeword indexing which can store general Prolog terms in external databases for fast retrieval by NU-Prolog programs; the database system makes use of the superjoin algorithm to perform efficient join operations * uses "when" declarations (the successor to MU-Prolog's "wait") to control the execution of NU-Prolog programs according to the availability of data * implements a large set of built-in predicates, including many Quintus Prolog predicates; most DEC-10/Edinburgh/MU-Prolog library predicates are available through compatibility libraries The NU-Prolog system contains the following major components: * "nc", the NU-Prolog compiler * "np", a simple interpreter-style interface which implements the standard Edinburgh Prolog style debugging facilities and has a sophisticated query language for accessing external database predicates * "nac", a program for adding control information to NU-Prolog programs written in a purely logical style * "nit", a program for reporting common errors in NU-Prolog programs (cf. Unix/C's "lint") NU-Prolog runs under Unix System V and Berkeley BSD Unix 4.?. It has been implemented on a large number of machines including the following: Sun 3 and 4, Vax, Encore, Elxsi, Perkin Elmer, Pyramid, Integrated Solutions Workstations. For academic licences, the system comes complete with a manual and all source code. The preferred distribution medium is 1/2" tape, Unix tar-format at 1600bpi. Other distribution media may be available on request. There is a A$400.00 fee to cover distribution costs. In order to obtain a copy of the system, you must first complete a licence agreement with the University of Melbourne. Licences can be obtained by contacting: NU-Prolog Distribution Department of Computer Science University of Melbourne Parkville, Victoria, 3052 AUSTRALIA or mip@munnari.oz + The Machine Intelligence Project has been assisted in the development of NU-Prolog by: the Commonwealth Department of Science, the Australian Research Grants Scheme, the University of Melbourne, Pyramid Technology, Aust, and Disc Computer Systems.