[avibryant]

Why not consider it a reader macro, and translate it to (@ foo bar) or whatever is appropriate, before applying macro expansion?

[sedachv]

I considered doing that, but it pretty much means rewriting the reader because it changes the grammar so much. Not that it's not possible, I just don't trust myself not to make it full of bugs.

[gruseom]

Seems possible. You'd have to make . be a macro character, which would ruin dotted lists, but Parenscript doesn't have those anyway.