The obvious way to handle strings is to turn the constants into symbols at expansion time, and dispatch on (string->symbol <input>), just like we handle chars by turning them into fixnums and using fixnum dispatch. After that, it's a question of whether you want case to work for lists, vectors, syntactic hash tables, whatever else. For my own part, those are better handled by `match.' (Well, maybe not hash tables.)
On Tue, Nov 20, 2012 at 9:15 AM, Hendrik Boom <hend...@topoi.pooq.com> wrote: > On Tue, Nov 20, 2012 at 07:42:46AM -0600, Robby Findler wrote: >> On Tue, Nov 20, 2012 at 12:14 AM, David T. Pierson <d...@mindstory.com> >> wrote: >> > On Mon, Nov 19, 2012 at 06:13:09AM -0700, Matthew Flatt wrote: >> >> Should we change `case' to use `equal?' instead of `eqv?'? I can't >> >> think of a good reason to stick with `eqv?'. >> > >> > My first reaction to this was that such a change would eliminate one of >> > the motivations for using `case': getting the (perhaps insignificant?) >> > performance improvement of using `eqv?' in a conditional when you know >> > the key type is suitable for it. >> > >> > However it occurs to me that since the datums in a `case' clause are >> > always literals, couldn't the expansion of `case' be "smart" enough to >> > use the appropriate comparison function (eq?/eqv?/equal?) given the type >> > of the datum? >> >> I think that equal? will always terminate quickly when its input is a >> symbol/number/boolean so the macro doesn't need to do anything special >> in that case. > > It could do a binary tree search on the data and use some kind of > ordering comnparison. > > By the way, it's a long time since I saw 'datums' as plural of 'datum'. > I wonder if it will become correct one of these years, since 'data' is > often misused as singular, as a substance noun instead of an object > noun. > > -- hendrik > ____________________ > Racket Users list: > http://lists.racket-lang.org/users ____________________ Racket Users list: http://lists.racket-lang.org/users
