I suspect that this bug is a feature request.

Anyway I coded another solution which sematics is more exact.
The idea is to quote ... and each match will remove one of the quotes around .... So now this works,

(sxml-match '(a (b (c 1) (c 2 3)) (b (c 4)) (b (c 5)))
 ((a ,x ...)
    (list (sxml-match x
               ((b ,y '...)
                   (list (sxml-match y
                            ((c ,z ''...) z)) '...))) ...)))

$1 = (((1) (2 3)) ((4)) ((5)))

attached is a git diff of the code.

the bad thing with this code is that it's not possible to output
the '... symbol.

/Stefan

(file #23968)

Ok here is a patch if it encounters a form like
 x ... in the output part of sxml-match it will check if there exists an ellipsis variable inside x. If there doesn't exist any it will not try to expand the ellipsis, but instead keep it verbatrim.

So the subsequent matches must not use previous pattern
variables inside their patterns for this to work.

/Stefan

(file #23945)

First, upstream doc's for sxml-match indicates that ellipsis
in the body is not allowed and then the the Bug would be moot
because the spec does not allow the example below.

On the other hand allowing the code below is a useful feature and
I have a patch that introduce this new feature. On the other hand
this means that guile code using sxml-match would not work on other platforms with the upstream version.

Best is possible to contact Jim Bender to include this as a feature.

The solution is to allow ellipsis in the body in the following way:
if we encounter (p ... . l) then p is investigated to see if there are any variables that comes from an ellipsis in the matcher. If we find that there exists such variables the ellipsis will not be used for expansion paths in the macro and it will be untouched.

Yeah, I have no idea. Maybe Jim Bender would be interested in this one; I'll forward the message.