Re: append 3 lists in the same time

[Henk Vandecasteele]

hi,

remark that:

> o( A, o( B, C)) :- append(A, B, X), o(X, C).
> o( X, X) :- X \= o(_, _).


has not linear complexity,
it will traverse the list A as many times as there are list to be
appended.

Regards,

Henk


Lindsey Spratt wrote:

> On Fri, Mar 29, 2002 4:36 AM, Gurvan Le Guernic <mailto:address@hidden>
> wrote:
>
> > instead of typing: append(A,B,L1), append(L1,C,L).
> > we could type something like: L=A o B o C.
>
> Here is one approach.
>
> If you'd be willing to type: A o B o C o L, where L is the "result" list,
> then this can be implemented in standard prolog using an operator.
>
> A possible implementation:
>
> :- op( 900, xfy, o).
>
> o( A, o( B, C)) :- append(A, B, X), o(X, C).
> o( X, X) :- X \= o(_, _).
>
> Examples:
> 'A o B o L.' -> 'append( A, B, L).'
> 'A o B o C o L.' -> 'append(A, B, X), append(X, C, L).'
>
> -lindsey
>
>
>
>
> _______________________________________________
> Users-prolog mailing list
> address@hidden
> http://mail.gnu.org/mailman/listinfo/users-prolog