Re: Impressed but confused, gluing a list together...

[Michał Bieliński]

Dnia 1 Października 2013, 23:50, Wt, Sean Charles napisał:
>> I added a cut to avoid the solution with trailing glue.
>> join([X], _, [X]) :- !.
>
> I am confused at the cut.. I have not yet experienced trailing glue,
> that was the point of the second rule!?

When I compiled your initial example and tested it GNU Prolog returned two
results.  I wanted only one.  The behavior without cut is this:

GNU Prolog 1.4.4 (32 bits)
Compiled Apr 29 2013, 20:41:58 with gcc
By Daniel Diaz
Copyright (C) 1999-2013 Daniel Diaz

| ?- join("ABC", "Z", X).

X = [97,[122],98,[122],99] ? ;

X = [97,[122],98,[122],99,[122]]

yes


With cut gprolog is satisfied with telling me the first solution.

-- 
Michał Bieliński