I'll study the matter further. Thanks for your suggestions. I'll need some time for study, but you can be assured I shall post my experiences. Thanks, Jos
-----Original Message----- From: Matthew Flatt [mailto:[email protected]] Sent: miércoles, 28 de septiembre de 2011 22:59 To: Jos Koot Cc: 'Racket-users' Subject: RE: [racket] case form implemented with a hash I had in mind the comment on page 64, bottom right, but I see that it's a smaller comment than in my memory. Overall, I think it will work better to use a hash table to go from a value to an index, and then use a binary search on the index as in Clinger's paper. Indirect dispatch via thunks in a hash table will most likely be slower. At Wed, 28 Sep 2011 22:55:08 +0200, "Jos Koot" wrote: > Hi Hatthew, > I am still trying to implement 'case' by means of a hash. > Can you give me a more specific pointer. I followed your pointer but did not > see anything relevant to my question. > Jos > > -----Original Message----- > From: Matthew Flatt [mailto:[email protected]] > Sent: miércoles, 28 de septiembre de 2011 22:20 > To: Jos Koot > Cc: 'Racket-users' > Subject: Re: [racket] case form implemented with a hash > > At Wed, 28 Sep 2011 22:08:44 +0200, "Jos Koot" wrote: > > By inspection with the macro stepper I found that case forms are expanded > to > > nested if-forms. For case forms with many clauses, this may be > inefficient. > > I have tried to prepare a hash-case form using a hash table in order to > > select the desired clause more efficiently. So far my attempts failed. I > am > > still trying. However, has anybody else on this list thought of using a > hash > > for case forms with many clauses? Does it exist? If not, would anyone be > > interested in a hash-case form that has the same shape as a case-form, but > > uses a hash-table to select the appropriate clause? The hash table should > be > > a map onto thunks and macro hash-case simply would have to retrieve the > > thunk and call it. > > See "Rapid Case Dispatch in Scheme", Clinger, Scheme'06. > > If you implement a revised `case' that consistently works better, then > I'd be happy to use it as a replacement for the current `case'. _________________________________________________ For list-related administrative tasks: http://lists.racket-lang.org/listinfo/users
