Re: [eclipse-clp-users] Problem using probe_sched

From: Kish Shen <kisshen_at_cisco.com>
Date: Wed, 14 Oct 2009 12:05:36 +0100
Riyadh Jemal wrote:

> My problem was similar to that faced by Simone Pascucci on the mailing
> list and it led me to suggest that some information including examples
> on the use of dynamic clauses be included in the tutorial.
>
Hi Riyadh,

The tutorial and examples do not include examples using dynamic 
predicates (i.e. clauses you can assert/retract) because there aren't 
many uses for them that are not better done with other features in 
ECLiPSe/Prolog. Support for dynamic predicates in ECLiPSe is mainly 
meant for backwards compatibility with Prolog (and also for the few 
cases where it is a good idea).

As you mentioned in your email to me, you assert the data you want to 
use as facts, and then use them. If the data is available before you run 
the program, then it is much better to generate a program with the facts 
in them, and compile this.

I assume you are using facts for your data because the examples I 
suggested you look at uses facts to store the data. This was mainly done 
this way because it is convenient to show everything in one file in the 
examples. A better approach if you want your code to work with different 
data set is to read in the data directly (using the I/O facilities of 
ECLiPSe), and create your data constraints from them, rather than having 
them as facts, and creating the constraints from the facts. Having the 
facts means you are duplicating the information, and makes it difficult 
if you want to run the program again with a different set of data.

Cheers,

Kish

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Received on Wed Oct 14 2009 - 11:05:52 CEST

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