On Friday, May 3, 2013, Ryan Culpepper wrote: <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">On 05/03/2013 11:12 AM, Robby Findler wrote: <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"> Can you point to some examples? Note that you can still use else, as long as you don't refer to it as a variable. </blockquote> Just to check: If match treats else specially, it should only accept it as the entire pattern. For example, the following should be an illegal use of else: (match x [(list 'if test then else) ___]) Right? (BTW, I may have written exactly the code above. I need to check.) </blockquote><div> </div><div>I would not midn if that bound 'else' as a variable.</div><div> </div><div>The only change I'd request is that when 'else' is the entire pattern, since that's the situation that's confusing to people not language lawyers.</div> <div> </div><div>Robby</div><div> </div><div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"> Ryan <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"> On Friday, May 3, 2013, J. Ian Johnson wrote: I've used else as a catch-all binding in match. Yes, it's not the best practice, but I think since I've done it, other people must have done it too. This could annoy them. -Ian ----- Original Message ----- From: "Robby Findler" <<a>robby@eecs.northwestern.edu</a> <javascript:;>> To: "Sam Tobin-Hochstadt" <<a>samth@ccs.neu.edu</a> <javascript:;>> Cc: <a>dev@racket-lang.org</a> <javascript:;> Sent: Friday, May 3, 2013 11:04:27 AM GMT -05:00 US/Canada Eastern Subject: Re: [racket-dev] else clauses: possible change to match? Given that we don't yet even have a prototype of racket2, I'm going to guess that "near" isn't all that near. IMO, there are other big things that we should be focused on going first (notably the package system). Just to check again: Is no one concerned with the backwards incompatibility issue? Robby On Friday, May 3, 2013, Sam Tobin-Hochstadt wrote: Right, I agree with this. My question is basically: are we going to, in the reasonably near future, be encouraging people to program in a `#lang racket2` where `cond` works differently, in which case it doesn't seem worth it to change `match`. Otherwise, I'll do this now. Sam On Fri, May 3, 2013 at 10:42 AM, Robby Findler < <a>robby@eecs.northwestern.edu</a> <javascript:;> > wrote: > Cond's else cannot change. I agree that that's what I would change if I > could have it back to do it over, but we cannot. > > That's the way to perhaps be thinking about racket2, tho. > > Robby > > > On Friday, May 3, 2013, Sam Tobin-Hochstadt wrote: >> >> On Fri, May 3, 2013 at 10:22 AM, Robby Findler >> < <a>robby@eecs.northwestern.edu</a> <javascript:;> > wrote: >> > >> > For this kind of thing, my preference would be to change match than to >> > issue >> > a warning. I don't like warnings that are basically admitting weaknesses >> > in >> > the language design.... Of course, changing a core thing like that may >> > be >> > more trouble than it is worth, due to backwards compatibility concerns, >> > which is why I think it is worth raising here to see what others think. >> >> I'm happy to make this change to `match`, except that I've heard >> Matthew say that he would have used a keyword for `else` in `cond` if >> he had it to do over again, and I wouldn't want to change one way, and >> then change back. >> >> Sam _________________________ Racket Developers list: <a href="http://lists.racket-lang.org/dev" target="_blank">http://lists.racket-lang.org/dev</a> _________________________ Racket Developers list: <a href="http://lists.racket-lang.org/dev" target="_blank">http://lists.racket-lang.org/dev</a> </blockquote> </blockquote>