pgne-mode is a emacs minor-mode that allows inserting the closing
pair of a syntax node. This doesn't sound too dissimilar from
electric-pair-mode, but in contrast to electric-pair-mode,
pgne-mode allows balancing character sequences based on the
treesit parse state. This, in theory, allows you to balance a ruby
def with a corresponding end.
I've incrementally gotten this to "work" in nix-ts-mode, where it can
insert balanced parens and let/in as well as if/then else
pairs. I'm semi-convinced that it'll work in other modes too, but
there are some still-glaring bugs and problems to iron out.
There is a californian utilities company that has a similar name, which is somewhat infamous for doing electricity to trees (causing forest fires), throwing the already-precipitous ecosystem there into a greater imbalance. It seemed fitting (and it's short).