So Haskell conventionally uses ' as a suffix, prime. From what I've seen, Scheme and Racket tend to use * instead.
At some point I "learned" that you cannot use ' as a suffix in Racket. Today I tried again, and was surprised to see that it works... somewhat. $ racket Welcome to Racket v6.1.1.6. -> (define x' 42) -> x' 42 -> (+ x' 10) '(+ x '10) -> (+ 10 x') ; readline-input:4:8: read: unexpected `)' -> (+ 10 x' ) ; readline-input:5:8: read: unexpected `)' 0. It turns out x' _is_ a valid identifier, and it self-evaluates just fine. Interesting. 1. I don't understand why (+ x' 10) evaluates not to 52, and not even an error, but... '(+ x '10). WAT. 2. Less surprising to me is that (+ 10 x') and even (+ 10 x' ) are errors. But actually, I wonder why the reader (or lexer?) couldn't handle ' followed by a character that can't be part of an identifier? p.s. I'm not proposing this would be a great suffix style to use. Quick, distinguish x' from 'x ! And don't type one when you mean the other! I get that. Even so, I'm curious. ____________________ Racket Users list: http://lists.racket-lang.org/users
