How to ignore variables in a Prolog query

[razetime]

In SWIPL I can prefix an _ to any variable to avoid the output of its potential values in the query output (here, _A):

?- member(_A,[[1],[2]]),member(B,_A).
B = 1 ;
B = 2.

How do I ask scryer prolog to "ignore" variables in a similar way?

[UWN]

Instead of explicitly ignoring some variables, you may just indicate the variables you are interested in:

?- use_module(library(lambda)).
   true.
?- B+\ ( member(A,[[1],[2]]), member(B,A) ).
   B = 1
;  B = 2.
?- [B,C]+\ ( member(A,[[1],[2]]), member(B,A), C = more ).
   B = 1, C = more
;  B = 2, C = more.

Note that suppressing the answers for named variables starting with an underscore collides with new variables in answers.

?- length(L,3).
   L = [_A,_B,_C].

This becomes a problem, if you want to paste back such answers into a further query.