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PySwip enables querying SWI-Prolog in your Python programs.

Project description

PySwip

What's New?

See the CHANGELOG.

This library is being cleaned up and refactored. Expect API breakage and incompatibility with previous versions.

Thanks to all contributors. If you have contributed to PySwip in the past and your name does not appear on that list, please let me know so I can add your name.

Introduction

PySwip is a 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.

Requirements:

  • Python 2.7 or 3.4 and higher.
    • PyPy is currently not supported.
  • SWI-Prolog 7.6.x and higher.
  • libswipl as a shared library. This is the default on most platforms.
  • Works on Linux, Windows and MacOS. Should work on other POSIX.

Install

See INSTALL for instructions.

Examples

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

An existing knowledge base stored in a Prolog file can also be consulted, and queried. Assuming the filename "knowledge_base.pl" and the Python is being run in the same working directory, it is consulted like so:

>>> from pyswip import Prolog
>>> prolog = Prolog()
>>> prolog.consult("knowledge_base.pl")

Foreign Functions

from __future__ import print_function
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)")    
print(list(prolog.query("father(michael,X), hello(X)")))

Pythonic interface (Experimental)

from __future__ import print_function
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.

Help!

Contact

Projects/Publications that Use or Reference PySwip

Do you have a project, video or publication that uses/mentions PySwip? Please let me know or send a pull request.

Books

Publications

Videos

Projects

Blog Posts

License

Copyright (c) 2007-2018 Yüce Tekol

Permission is hereby granted, free of charge, to any person obtaining a copy of
this software and associated documentation files (the "Software"), to deal in
the Software without restriction, including without limitation the rights to
use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
the Software, and to permit persons to whom the Software is furnished to do so,
subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

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Filename, size & hash SHA256 hash help File type Python version Upload date
pyswip-0.2.7-py2.py3-none-any.whl (24.1 kB) Copy SHA256 hash SHA256 Wheel py2.py3 Jun 7, 2018
pyswip-0.2.7.tar.gz (21.2 kB) Copy SHA256 hash SHA256 Source None Jun 7, 2018

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