NOTE: development in YAP migrated to the yap repo (v7). This repo is here for compatibility.

This document provides User information on version 6.3.4 of YAP (Yet Another Prolog). The YAP Prolog System is a high-performance Prolog compiler developed at Universidade do Porto. YAP supports stream Input/Output, sockets, modules, exceptions, Prolog debugger, C-interface, dynamic code, internal database, DCGs, saved states, co-routining, arrays, threads.

We explicitly allow both commercial and non-commercial use of YAP.

YAP is based on the David H. D. Warren's WAM (Warren Abstract Machine), with several optimizations for better performance. YAP follows the Edinburgh tradition, and was originally designed to be largely compatible with DEC-10 Prolog, Quintus Prolog, and especially with C-Prolog. More recently, we have worked on being compatible with SICStus Prolog and with SWI-Prolog.

YAP implements most of the ISO-Prolog standard. We are striving at full compatibility, and the manual describes what is still missing. The document is intended neither as an introduction to Prolog nor to the implementation aspects of the compiler. A good introduction to programming in Prolog is the book @cite TheArtOfProlog , by L. Sterling and E. Shapiro, published by "The MIT Press, Cambridge MA". Other references should include the classical @cite ProgrammingInProlog , by W.F. Clocksin and C.S. Mellish, published by Springer-Verlag.

YAP 6.3.4 has been built with the gcc and clang compilers on Linux and OSX machines. We expect to recover support for WIN32 machines and Android next.

We are happy to include in YAP several excellent packages developed under separate licenses. Our thanks to the authors for their kind authorization to include these packages.

The overall copyright and permission notice for YAP4.3 can be found in the Artistic file in this directory. YAP follows the Perl Artistic license, and it is thus non-copylefted freeware. Some components of YAP have been obtained from SWI Prolog and ciao, and have different licenses.

If you have a question about this software, desire to add code, found a bug, want to request a feature, or wonder how to get further assistance, please send e-mail to . To subscribe to the mailing list, visit the page https://lists.sourceforge.net/lists/listinfo/yap-users.

On-line documentation is available for YAP

The packages are, in alphabetical order:

• The CHR package developed by Tom Schrijvers, Christian Holzbaur, and Jan Wielemaker.

• The CLP(BN) package and Horus toolkit developed by Tiago Gomes, and Vítor Santos Costa.

• The CLP(R) package developed by Leslie De Koninck, Bart Demoen, Tom Schrijvers, and Jan Wielemaker, based on the CLP(Q,R) implementation by Christian Holzbaur.

• The CPLint package developed by Fabrizio Riguzzi's research laboratory at the University of Ferrara

• The CUDA interface package developed by Carlos Martínez, Jorge Buenabad, Inês Dutra and Vítor Santos Costa.

• The GECODE interface package developed by Denys Duchier and Vítor Santos Costa.

• The JPL (Java-Prolog Library) package developed by .

The minisat SAT solver interface developed by Michael Codish, Vitaly Lagoon, and Peter J. Stuckey.

• The MYDDAS relational data-base interface developed at the Universidade do Porto by Tiago Soares, Michel Ferreira, and Ricardo Rocha.

• The PRISM logic-based programming system for statistical modeling developed at the Sato Research Laboratory, TITECH, Japan.

• The ProbLog 1 system developed by the ProbLog team in the DTAI group of KULeuven.

• The R interface package developed by Nicos Angelopoulos, Vítor Santos Costa, João Azevedo, Jan Wielemaker, and Rui Camacho.