Comment by Syzygies

I've used something like this for Lisp-family languages privately for decades.

[1] I like having a bar | open a parenthesis that closes automatically when the line or group ends.

[2] There are many Lisp/Scheme constructions that jump two deep without an intervening symbol. Rather that having to count out indents, it's very helpful and readable to have a dummy symbol as skeleton to reify the parenthesis structure. I like $ from Haskell.