Allow binding of partially applied operator functions

[apaleslimghost]

I keep finding myself wanting to use (.a is @b) but of course it doesn't work. I have to fall back on ~>it.a is @b (or (.a is this$.b), shudder). Can we have something like ~(.a is @b)?

[apaleslimghost]

Or better still, have pre- (or post-) fix ~ as .bind this?

[apaleslimghost]

Hmm, seems I'm repeating myself (#249).

[vendethiel]

Might be not so pretty since we lex ~ as DOT. Could lex it otherwise if next is not able?

[vendethiel]

@gkz should every section be this-bound (we'd need to traverse the body to conditionally add it, maybe)

[vendethiel]

I know this is the oldest, but the other one got more reactions, so #634.