No, you recall correctly. We conducted this experiment a long time ago (w/o inserting else clauses though as far as I recall). That is, when the code base was small compared to what we have now.
I forgot why the issue came up but there was an additional, external impetus. The cond issue also shows up in TR. We should and will have to tackle it. ;; --- Racket2: we start from TR and move backwards :-) On Oct 2, 2012, at 10:43 AM, Robby Findler wrote: > On Tue, Oct 2, 2012 at 9:39 AM, Carl Eastlund <c...@ccs.neu.edu> wrote: >> I'm not surprised, I pretty much expected this response, but I'm curious >> what the difficulty was. Is cond-as-void relied on that much more >> pervasively than mutable pairs? > > I'm not sure I can comment on the relative reliance, but in the case > of mutable pairs, we had a lot at stack (ie many abstractions are > broken in their presence). That's not the case with the cond/void > situation. > >> Is it exceedingly hard to add else-clauses >> to all the necessary conds? You two, Robby and Matthew, probably have a >> better idea than I do about the prevailing trends in the Racket code base. > > I don't think we considered writing a script to stick else clauses in. > We just were surprised at how often it was relied on and decided to > give up. (But memory is a fragile thing, so I could be getting this > completely wrong.) > > Robby > >> Carl Eastlund >> >> >> On Tue, Oct 2, 2012 at 10:36 AM, Robby Findler <ro...@eecs.northwestern.edu> >> wrote: >>> >>> IIRC, we even experimented with this one briefly and quickly gave up >>> as we got overwhelmed. >>> >>> Robby >>> >>> On Tue, Oct 2, 2012 at 9:22 AM, Matthew Flatt <mfl...@cs.utah.edu> wrote: >>>> I think this a great change for a future `racket2' (someone should be >>>> keeping a list of these), but it's too incompatible a change for `cond' >>>> in `racket'. >>>> >>>> At Tue, 2 Oct 2012 09:52:38 -0400, Carl Eastlund wrote: >>>>> 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: >>>>> http://lists.racket-lang.org/dev >>>> _________________________ >>>> Racket Developers list: >>>> http://lists.racket-lang.org/dev >>> >> > _________________________ > Racket Developers list: > http://lists.racket-lang.org/dev _________________________ Racket Developers list: http://lists.racket-lang.org/dev
