Re: what's the corresponding predcate as atomic_list_concat in swi

Le 28/06/2013 00:15, z_axis a écrit :
> Can it convert '1 2 3 4 5 6 7' to [1,2,3,4,5,6,7] ?
> IIRC,in swi, atomic_list_concat('1 2 3 4 5 6 7', ' ', X).  => X = 
> [1,2,3,4,5,6,7]
>
> Best Regards!
> 在 Thu, 27 Jun 2013 02:22:15 +0800，Daniel Diaz 
> <[email protected]> 写道:
>

You need to program it. Here is a simple program that split an atom 
(elements are separated by spaces). Each atom of an element is converted 
to the final type with conv_elem/2. Here it is defined to convert atoms 
to numbers. If you want atoms for elements simply define conv_elem(A, A).

atom_to_list('', []) :-
     !.

atom_to_list(A, L) :-
     sub_atom(A, Bef, _, Aft, ' '), !,
     (   Bef > 0 ->
         L = [X|L1],
         sub_atom(A, 0, Bef, _, A0),
         conv_elem(A0, X)
     ;
         L = L1
     ),
     Bef1 is Bef + 1,
     sub_atom(A, Bef1, Aft, 0, A1),
     atom_to_list(A1, L1).

atom_to_list(A, [X]) :-
     conv_elem(A, X).


conv_elem(A, X) :-
     number_atom(X, A).

Run:

| ?- atom_to_list('1 2 3 4 5 6 7',L).

L = [1,2,3,4,5,6,7]

Daniel

>> Hi,
>>
>> the easiest way to convert numbers to atoms and then use 
>> atom_concat/3. This should work:
>>
>> atomic_concat(X1, X2, A3) :-
>>     to_atom(X1, A1),
>>     to_atom(X2, A2),
>>     atom_concat(A1, A2, A3).
>>
>> to_atom(A, A) :-
>>     atom(A), !.
>>
>> to_atom(X, A) :-
>>     number_atom(X, A).
>>
>>
>> Daniel
>>
>> Le 26 juin 2013 à 08:39, Sean Charles <[email protected]> a écrit :
>>
>>> Hi z_axis,
>>>
>>> I looked long and hard and I couldn't find anything suitably matched 
>>> in the atom and character code sections … sorry.
>>>
>>> I think somebody that *knows* the language has an opportunity to 
>>> hand-roll something at this point… I will also try to do this as an 
>>> exercise, it will be good to try.
>>>
>>> My initial thought would be to use a stream writing to an atom, then 
>>> write each atom in the original list plus the intervening comma for 
>>> all but the last atom.
>>>
>>>    open_output_atom_stream ...
>>>    write_term_to_atom  … each list member plus a comma
>>>    close_output_atom_stream ...
>>>
>>> Simples. Except I just have to do it. And if it could be used 
>>> "backwards" to split the atom then so much the better, like SWI.
>>>
>>> I am sure somebody else will do it first but I like the look of this 
>>> so I shall try as well.
>>>
>>> Sean.
>>>
>>>
>>>
>>>
>>> On 26 Jun 2013, at 03:15, z_axis <[email protected]> wrote:
>>>
>>>> It seems there is just atomic_concat in gprolog ?
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>
>


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