<div dir="ltr"><div class="gmail_default" style="font-family:courier new,monospace">Welcome to DrRacket, version 6.0.1 [3m]. Language: racket/base [custom]; memory limit: 4096 MB. > (string->symbol "x'") '|x'| </div></div><div class="gmail_extra"> <div class="gmail_quote">On Thu, Jan 8, 2015 at 3:15 PM, Greg Hendershott <<a href="mailto:greghendershott@gmail.com" target="_blank">greghendershott@gmail.com</a>> wrote: <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">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: <a href="http://lists.racket-lang.org/users" target="_blank">http://lists.racket-lang.org/users</a> </blockquote></div> </div>