Re: reset in gprolog

[Daniel Diaz]

Hi,

there is no reset in GNU Prolog, each predicate loaded by consult erase 
an existing definition (if any). You can use an undocumented predicate 
to remove a predicate '$remove_predicate'(Pred, Arity). Here is a 
possible definition for reset:

reset :-
        (   current_predicate(P/N),
            '$remove_predicate'(P, N),
            fail
        ;
            true).

Obviously, if you consult this definition it will be also removed when 
you use reset. You can compile a file called mygprolog.pl with only this 
definition:

% file mygprolog.pl
:- built_in.

reset :-
        (   current_predicate(P/N),
            '$remove_predicate'(P, N),
            fail
        ;
            true).

then compile it with:

gplc myprolog.pl

lauching mygprolog you obtain a new top-level with reset as a new built-in.

Hope this helps.

Harendra Narayan wrote:
> Hi,
>
> I am trying to use 'reset' in gprolog interactive environment, but I am 
> not able to use it. What is the way to use it ?
>
> The basic purpose is as follows:
> I use "consult('test.prolog')." to read from a prolog file. Now I 
> modified the file and want to read it again, but before that I want to 
> reset the prolog environment as if it has just started (i.e. only the 
> inbuilt predicates are available). I think reset is the one which will 
> serve this purpose but I am not able to use it. I always get "uncaught 
> exception:error...".
>
> Thanks in advance for the help.
> Harendra

--
===============================================
                 Daniel Diaz
University of Paris 1      INRIA Rocquencourt
75013 Paris FRANCE      78153 Le Chesnay FRANCE
        web: http://pauillac.inria.fr/~diaz
        email: address@hidden

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