Indeed, I tried it for a while and didn't like it. I use * instead of ' for primes in my code. I think that's pretty common practice. -Ian
----- Original Message ----- From: "robby" <[email protected]> To: "Jon Zeppieri" <[email protected]> Cc: "users" <[email protected]> Sent: Thursday, January 8, 2015 3:45:55 PM Subject: Re: [racket] Racketrivia: Using ' as an identifier suffix That's a scary convention. It's hard for humans to see the difference! On Thu, Jan 8, 2015 at 2:32 PM, Jon Zeppieri <[email protected]> wrote: > You can use the unicode prime character (′) as a suffix. In DrRacket, > you can type that as \prime followed by ctrl-\. It would be a lot > nicer to map it to a simple key combo like λ is, > > -Jon > > > On Thu, Jan 8, 2015 at 3:15 PM, Greg Hendershott > <[email protected]> wrote: >> 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 > > ____________________ > Racket Users list: > http://lists.racket-lang.org/users ____________________ Racket Users list: http://lists.racket-lang.org/users ____________________ Racket Users list: http://lists.racket-lang.org/users
