Sean Whitton writes:

Hello,

Okay, thanks, I understand better now what you're trying to accomplish.

This isn't fundamentally about comments at all. For example, these
multichar pairs could include the opening "case" and closing "esac" in a
shell script, right?

Honestly, I always had in mind that it would be for comments.

So if your type /*, it will automatically insert

/* */

^ cursor in middle both spaces

(including spaces an maybe newlines)

It was similar to what I saw in the cc modes and smartparens-mode

If that's right, then I'm not sure a new electric minor mode is the
right thing. We already have abbrevs and skeletons which work for this
sort of thing. Indeed, this is exactly how sh-case is already
implemented.

But those do not expand immediately AFAIK; like if you type "{"