bagof/3

[infradig]

Just passing this on:

$ cat q.pl
q(A, _, A).
q(_, A, A).
q(A, _, A).

$ scryer-prolog q.pl
?- bagof(none, q(X,Y,Z), L).
   X = Z, L = [none]
;  Y = Z, L = [none]
;  X = Z, L = [none].
?- 

should be:

$ gprolog
GNU Prolog 1.6.0 (64 bits)
| ?- [q].
(1 ms) yes
| ?- bagof(none, q(X,Y,Z), L).
L = [none, none]
Z = X ? ;
L = [none]
Z = Y
yes

As per SWI, SICStus, Eclipse, Ciao.

[hurufu]

Similar to #2499

[UWN]

Similar to #2499

No, #2499 was related to goal expansion.

[UWN]

Shorter:

?- bagof(t, (X = Z ; Y = Z ; X = Z ), L).
   X = Z, L = "t", unexpected
;  Z = Y, L = "t"
;  X = Z, L = "t", unexpected.
   X = Z, L = "tt" % expected, but not found
;  Z = Y, L = "t"
|  other_answer_sequence.

[UWN]

Just passing this on:

From trealla#614.

[UWN]

Shortest (?):

?- bagof(t, ( true ; X = Y ; true ), L).
   L = "t", unexpected
;  X = Y, L = "t"
;  L = "t", unexpected.
   L = "tt" % expected, but not found
;  X = Y, L = "t"
|  other_answer_sequence.