<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <HTML><HEAD> <META content="text/html; charset=us-ascii" http-equiv=Content-Type> <META name=GENERATOR content="MSHTML 9.00.8112.16434"></HEAD> <BODY bgColor=#ffffff text=#000000> <DIV dir=ltr align=left>A vector with closures is (in my case) hardly faster than a normal case form without closures.</DIV> <DIV dir=ltr align=left>See my other post on using a binary search without closures. In my case a gain of 10% only.</DIV> <DIV dir=ltr align=left>Jos</DIV> <DIV dir=ltr lang=en-us class=OutlookMessageHeader align=left> <HR tabIndex=-1> From: Neil Van Dyke [mailto:neil@neilvandyke.org] Sent: jueves, 29 de septiembre de 2011 17:10 To: Jos Koot Cc: 'Matthew Flatt'; 'Racket-users' Subject: Re: [racket] case form implemented with a hash </DIV> <DIV></DIV> <BLOCKQUOTE cite=mid:337B27C48DA04BF9B2B230C37DE03327@samsungPC type="cite"> At Thu, 29 Sep 2011 12:25:16 +0200, "Jos Koot" wrote: > In my case I have a case form which dispatches on a character, 86 different > ones. Therefore I can dispatch by means of a vector. However, almost every > character has its own clause and therefore dispatching on the index of the > character would give no speed up.</BLOCKQUOTE> Do I understand correctly that this jump-table-like vector-of-closures is not fast enough? If this were assembler for a conventional architecture, and you were doing a DFA-like lexer, I'd think that a jump table would be quite fast (but with some bloated constant for code size). I wonder whether there's an optimization the compiler/JIT can make that would be a big help, perhaps with additional hints from the Racket code?  And if so, would that optimization likely be useful for anything other than optimizing "case" of characters? <DIV class=moz-signature>-- <A class=moz-txt-link-freetext href="http://www.neilvandyke.org/">http://www.neilvandyke.org/</A> </DIV></BODY></HTML>