Or even use plain old := for assignment to help avoid confusion with ==. I wonder if K & R wanted to save a character for terseness. I mean, these are the guys who said, if they were writing Unix again, would "spell creat with an e."

https://en.wikiquote.org/wiki/Ken_Thompson

Or use ML-style reference cells, so that assignment cannot work on two things of the same type.

Now you're thinking with ~portals~ monads.