newbie question 4-9

Hello,

I'm just getting started with Prolog. I'm using the Clocksin & Mellish
book and SWI-Prolog v.5.6.9 as my environment.

I am trying out the examples, but I'm encountering some problems when
using if ":-".

When I try using :-, I keep getting the following error -

ERROR: Undefined procedure: (:-)/2


From the book I'm using the following:

likes(mary, books).
likes(mary, wine).
likes(john, france).

Wne I try the below in SWI, I get the error

?- likes(john, X) :- likes(X, wine).

ERROR: Undefined procedure: (:-)/2
?-
.

Relevant Pages

  • newbie question
    ... I'm using the Clocksin & Mellish ... book and SWI-Prolog v.5.6.9 as my environment. ... ?- likes:- likes(X, wine). ...
    (comp.lang.prolog)
  • Re: Hi I have a suggestion! To Imporve the perfect Freebsd!
    ... > programs and 3D applications won't even run with wine. ... Let me add my frustration to the beautiful world of free Unix software. ... I'm working in physical chemistry environment at the university. ... Now there is a commercial Unix alternative: Tecplot. ...
    (freebsd-questions)
  • Re: windows tcl/tk bug does not appear under Wine
    ... My guess is that when running in the Wine environment, ... When MS Windows Tcl is run from a Starpack on Linux under Wine, ...
    (comp.lang.tcl)
  • Re: running lightwave on Linux
    ... So long as you use Wine to provide the MSWindows ... environment. ... See the Frankscorner article re install and run ...
    (comp.os.linux.x)