Let's not piggy-back too much on this one change. First of all, I'm proposing a very simple change, albeit with potentially complex consequences; you've got a somewhat more complex design change in mind, but entirely backwards compatible. Second, you detect definitions by using "define" as a keyword? No, thank you, sir. Let me know when you have a design that allows arbitrary definitions. Personally I think this concept will work better as a new macro than an add-on for cond, because you're turning the already-overloaded test position, which can be an expression or a cond-specific keyword, into a triple-overload including definition special form names. Carl Eastlund <div class="gmail_quote">On Tue, Oct 2, 2012 at 10:11 AM, Jay McCarthy <<a href="mailto:jay.mccarthy@gmail.com" target="_blank">jay.mccarthy@gmail.com</a>> wrote: <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"> In addition to this, I want internal definitions in conds: (cond [test1 body1] (define var ...) [(test2 var) body2] [(test3 var) body3]) I have a macro that does these things: <a href="https://github.com/jeapostrophe/exp/blob/master/condd.rkt" target="_blank">https://github.com/jeapostrophe/exp/blob/master/condd.rkt</a> It's pretty cute Jay <div class="HOEnZb"><div class="h5"> On Tue, Oct 2, 2012 at 7:58 AM, Carl Eastlund <<a href="mailto:cce@ccs.neu.edu">cce@ccs.neu.edu</a>> wrote: > Oh, no, as far as a "does it work out of the box" experiment goes, it fails. > Racket doesn't even compile. I meant more along the lines of our > immutable-cons experiment, where we fix a bunch of code and see how > problematic the compatibility issue becomes over time. > > Carl Eastlund > > > On Tue, Oct 2, 2012 at 9:56 AM, J. Ian Johnson <<a href="mailto:ianj@ccs.neu.edu">ianj@ccs.neu.edu</a>> wrote: >> >> This experiment should be easy to run, no? Change the default cond and run >> DrDr? >> -Ian >> ----- Original Message ----- >> From: "Carl Eastlund" <<a href="mailto:cce@ccs.neu.edu">cce@ccs.neu.edu</a>> >> To: "Racket Developers" <<a href="mailto:dev@racket-lang.org">dev@racket-lang.org</a>> >> Sent: Tuesday, October 2, 2012 9:52:38 AM GMT -05:00 US/Canada Eastern >> Subject: [racket-dev] Falling through cond clauses >> >> >> I often wish cond would raise an exception if all the tests failed and >> there were no else clause. I have taken to writing a macro to enforce this; >> I usually call it cond!. The void default for cond seems like an >> un-Racketish holdover from primarily-imperative programming. With some of >> the other changes we've made in Racket, are we willing to consider changing >> the fall-through behavior of cond? It seems like an experiment worth running >> to me. >> >> If not, I would at least like to add an erroring version of cond somewhere >> in the language. It's a shame to have to keep writing such a primitive >> feature. Right now in my dracula github repo I have cond! implemented in >> racket/cond and re-exported from racket, but I'm not thrilled about either >> the location or the name. I kept it out of racket/base so I could depend on >> the syntax collection for good source location reporting in the error >> message. >> >> Carl Eastlund >> >> _________________________ >> 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> > </div></div>-- Jay McCarthy <<a href="mailto:jay@cs.byu.edu">jay@cs.byu.edu</a>> Assistant Professor / Brigham Young University <a href="http://faculty.cs.byu.edu/%7Ejay" target="_blank">http://faculty.cs.byu.edu/~jay</a> "The glory of God is Intelligence" - D&C 93 </blockquote></div>