PySWIP README ============ :Version: 0.2.2 :Author: Yuce Tekol. :Project Website: http://code.google.com/p/pyswip Introduction ------------ PySWIP is a GPL'd Python - SWI-Prolog bridge enabling to query SWI-Prolog in your Python programs. It features an (incomplete) SWI-Prolog foreign language interface, a utility class that makes it easy querying with Prolog and also a Pythonic interface. Since PySWIP uses SWI-Prolog as a shared library and ctypes to access it, it doesn't require compilation to be installed. Note that this version of PySWIP is slightly incompatible with 0.1.x versions. Requirements: ------------- * Python 2.3 and higher. * ctypes 1.0 and higher. * SWI-Prolog 5.6.x and higher (most probably other versions will also work). * libpl as a shared library. * Works on Linux and Win32, should work for all POSIX. Example (Using Prolog): ----------------------- >>> from pyswip import Prolog >>> prolog = Prolog() >>> prolog.assertz("father(michael,john)") >>> prolog.assertz("father(michael,gina)") >>> list(prolog.query("father(michael,X)")) [{'X': 'john'}, {'X': 'gina'}] >>> for soln in prolog.query("father(X,Y)"): ... print soln["X"], "is the father of", soln["Y"] ... michael is the father of john michael is the father of gina Since version 0.1.3 of PySWIP, it is possible to register a Python function as a Prolog predicate through SWI-Prolog's foreign language interface. Example (Foreign Functions): ---------------------------- from pyswip import Prolog, registerForeign def hello(t): print "Hello,", t hello.arity = 1 registerForeign(hello) prolog = Prolog() prolog.assertz("father(michael,john)") prolog.assertz("father(michael,gina)") list(prolog.query("father(michael,X), hello(X)")) Outputs: Hello, john Hello, gina Since version 0.2, PySWIP contains a 'Pythonic' interface which allows writing predicates in pure Python (*Note that interface is experimental.*) Example (Pythonic interface): ----------------------------- from pyswip import Functor, Variable, Query assertz = Functor("assertz", 2) father = Functor("father", 2) call(assertz(father("michael","john"))) call(assertz(father("michael","gina"))) X = Variable() q = Query(father("michael",X)) while q.nextSolution(): print "Hello,", X.value q.closeQuery() Outputs: Hello, john Hello, gina The core functionality of ``Prolog.query`` is based on Nathan Denny's public domain prolog.py found at http://www.ahsc.arizona.edu/~schcats/projects/docs/prolog-0.2.0.html Install ------- Please see ``INSTALL`` for detailed instructions.