for loop in prolog - PROLOG

On Tue, 10 Jan 2006 21:29:20 +0200, nobody wrote:

> hi to all,
>
> How could i implement a for loop in prolog. Let's say for
> example that i have an integer variable X and i want to repeat X times a
> specific action. Any idea welcome...

I'm a beginner myself, but I think it would be something like this:

do_n_times(0):- !.
do_n_times(N):-
%do actions,
NewN is N-1,
do_n_times(NewN).

--
"Don't worry about people stealing your ideas. If your ideas are any
good, you'll have to ram them down people's throats."
-- Howard Aiken

nobody wrote:
> hi to all,
>
> How could i implement a for loop in prolog. Let's say for
> example that i have an integer variable X and i want to repeat X
> times a specific action. Any idea welcome...


?- between(1, 5, X), write(X), nl, fail.
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5

No

% The fail/0 prevents my prolog processor from asking for each X
% whether to continue or not.

Roland

% my_for(start_value,end_value,increment,action)
my_for(V,V,_,_) :- !.
my_for(Start,End,Inc,Action) :-
End > Start,
NewValue is Start+Inc,
call(Action),
my_for(NewValue,End,Inc,Action).

"nobody" <nobody@do-not-spam.me> escreveu na mensagem
newsan.2006.01.10.19.29.18.959870@do-not-spam.me...
> hi to all,
>
> How could i implement a for loop in prolog. Let's say for
> example that i have an integer variable X and i want to repeat X
> times a specific action. Any idea welcome...

On 2006-01-16, Diogo Bastos <damrho@netcabo.pt> wrote:
> % my_for(start_value,end_value,increment,action)
> my_for(V,V,_,_) :- !.
> my_for(Start,End,Inc,Action) :-
> End > Start,
> NewValue is Start+Inc,
> call(Action),
> my_for(NewValue,End,Inc,Action).

Nice, but if you want to go into the trouble of proving a start
and a step, you probable want to pass the current value to the action
predicate. The following however won't work:

?- my_for(0, 10, 1, writeln(X)).

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....

--- Jan

> "nobody" <nobody@do-not-spam.me> escreveu na mensagem
> newsan.2006.01.10.19.29.18.959870@do-not-spam.me...
>> hi to all,
>>
>> How could i implement a for loop in prolog. Let's say for
>> example that i have an integer variable X and i want to repeat X
>> times a specific action. Any idea welcome...
>
>