[Feature request] Nested label scopes

[Rangi42]

(Note this this is independent from the concept of "scopes" for symbols in general, which would allow shadowing of outer symbols and auto-purging when the scope ends; see #342.)

Currently there's only one level of symbol scoping: .local symbols are scoped to their preceding Parent. It might be useful to have more levels, in the manner described by ax6:

..foo to define a label in the second-level nested scope would be some simple syntax that could be used. Like so:

Main:
  dw 1234
: ..label isn't allowed here (nonsensical nested label; no parent)
.foo
  dw 5678
..bar ; defines Main.foo.bar
  dw 9012
.baz ; defines Main.baz (up a level because it only has one dot)
  dw 34567

Naturally, ...label would be a third level, etc. Explicit definitions (.foo.bar, Main.foo.bar:) should also work.

It could autofill each upper level separately: so appending Main..bar there would become Main.baz.bar, appending .baz.qux would become Main.baz.qux (and then appending .baz..spam would become Main.baz.qux.spam).

[Rangi42]

One use case:

wShadowOAM::
    for i, OAM_COUNT
        .obj{d:I}::
            ..y:: db
            ..x:: db
            ..tile:: db
            ..attr:: db
    endr

That lets you do ld [wShadowOAM.obj2.tile], $42.

[Rangi42]

fasm has this, including ..foo and ./.. functionaity.

[Rangi42]

customasm has this as well.