Search code examples
pythonprologffiswi-prolog

Call prolog predicate from python

I have some .pl file and I want to call predicate declared in it from python script. How can I do that?

For example, test.pl

rD( [], Ans, Ans ).
rD( [X|Xs], Ans, Acc ) :-
    member( X, Acc ),
    rD( Xs, Ans, Acc ), !.
rD( [X|Xs], Ans, Acc ) :-
    \+member( X, Acc ),
    append( Acc, [X], AccNew ),
    rD( Xs, Ans, AccNew ), !.

Working like 

?- rD( [1,2,3,4,5,4], X ).
X = [1, 2, 3, 4, 5].

I want to call rD somehow from python script and get answer in result variable

result
[1, 2, 3, 4, 5]

ps: it is just an example, and I don't want to rewrite my current Prolog program.

Solution

  • Not that I have a direct experience with it, but there is a project called PySWIP that provides a bridge between Python and SWI-Prolog. The wiki hosted on Google Code's project pages holds installation instructions and some usage examples.

    EDIT (5th of July 2019)

    PySWIP now seems to be maintained on Github, with its own installation instructions. TLDR: installing SWI-Prolog and pip install pyswip should do the job, for both Python 2 and 3.