Newbie question about 'pce_begin_class'

[dfkettle]

Hi!

I've just started using SWI-Prolog and XPCE, and I'm going through the tutorial "XPCE/Prolog Course Notes", but when I tried to enter the example in section 3.3.3, I received this error message:

 ?- pce_begin_class(matrix(width, height), vector, "Two-dimensional array").

ERROR: toplevel: Undefined procedure: pce_begin_class/3 (DWIM could not correct goal)

I searched the Wiki page for this error and found this note:

Load XPCE explicitely by starting a file or module that uses it with the load-command:

:- use_module(library(pce)).

However, I had already done that, but I still get the error. What am I doing wrong?

Thanks.

[Anne Ogborn]

Did you type this in at the interactor (the ?- prompt? )

that goes in a file.

Prolog doesn't exactly have a 'repl', it has an 'interactor (also known as a top-level), it's where you enter queries.

Facts and rules go in a file you consult.

Explanation of this:

http://www.pathwayslms.com/swipltuts/student/index.html#not_repl








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From: dfkettle <dfke...@gmail.com>
To: swi-p...@googlegroups.com
Sent: Monday, November 10, 2014 11:43 AM
Subject: [SWIPL] Newbie question about 'pce_begin_class'

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[dfkettle]

Thanks, I didn't realize that. It makes sense now.