why not
local [x scoped], [y const], ...
I chose () because this is the "least special" kind of brackets.
I would not mind square brackets, simply because this would entail fewer keystrokes for me, but users of other keyboard layouts might disagree.
Any other characters might be used there equally well, but it is probably reasonable to use something that traditionally implies grouping, and it is not clear to me why multi-char sequences would be advantageous here.
Cheers,
V.
