Standard-library style, perhaps.
drop 3 “abcde” is “de”
is one example, and could work in multiple ways:
drop X "abcde" is "de"
would set X == 3, much like how string_concat runs backwards, and then of course it would work forwards.
https://github.com/users/robsimmons/projects/1/views/1?pane=issue&itemId=66607153