I'd like "Ctrl+A" to slowly expand the code selection, rather than highlight everything

[StachuDotNet]

In Dynalist, Ctrl-A slowly expands the scope of what I'm currently selecting rather than selecting all text available.

I love this feature. It makes it super ergonomic to copy and manipulate the structured text.
I think this would be appropriate for Dark as well - each Ctrl+A would expand just by one layer (pattern/expr/etc).
Even better, this could work on a AstRef level (e.g. so a ctrl+a on 1|2.34 would first just highlight 12)

[pbiggar]

I've wanted something like this for a while - paredit, on which our concept of the structured editor is based, has similar capabilities.

I don't want to use ctrl-a for it though - that already has a standard (select-all) meaning.