Re: append 3 lists in the same time

[Lindsey Spratt]

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