Creating a comma-separated list of space-separated lists — erroneus append() behavior

I’m trying to create a comma-separated list of space-separated lists with append().

I expect to get the following meta-list: ( (1 2), (3 4) ).

The problem is that append() breaks the first sub-list, producing ( 1, 2, (3 4) ).

$meta-list: append( ((1 2)), (3 4), comma)
@warn $meta-list
// WARNING: 1, 2, 3 4

@warn nth($meta-list, 1)
// WARNING: 1

// Just to make sure:
@warn @warn nth( ( (1 2), (3 4) ), 1)
//WARNING: 1 2

[Anahkiasen]

Creating a comma-separated list of space-separated lists

Yo dawg I heard you liked lists so we put a list in your list so can loop while you loop.

[nex3]

@lolmaus as @robwierzbowski pointed out, adding an extra set of parentheses doesn’t create an extra level of list nesting. Parentheses aren’t list delimiters; they just group order of operations. ($a) is always the same as $a.

This definitely seems like a bug though — no matter what you do with a single dimensional list, even if it’s explicitly space separated, append() with a comma separator turns it into a comma separated list.

$space-list: join(1, 2, space);
@debug append($space-list, (3 4), comma); // 1, 2, 3 4

This is the expected behavior. From the documentation of append:

If [the $separator argument] is comma or space, that is always the separator; if [it] is auto (the default), the separator is the same as that used by the list.