Path: csiph.com!weretis.net!feeder6.news.weretis.net!news.misty.com!news.iecc.com!.POSTED.news.iecc.com!nerds-end From: George Neuner Newsgroups: comp.compilers Subject: Re: Learning only one lexer made me blind to its hidden assumptions Date: Thu, 14 Jul 2022 16:46:36 -0400 Organization: A noiseless patient Spider Lines: 22 Sender: news@iecc.com Approved: comp.compilers@iecc.com Message-ID: <22-07-017@comp.compilers> References: <22-07-006@comp.compilers> <22-07-010@comp.compilers> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 8bit Injection-Info: gal.iecc.com; posting-host="news.iecc.com:2001:470:1f07:1126:0:676f:7373:6970"; logging-data="49458"; mail-complaints-to="abuse@iecc.com" Keywords: lex, performance Posted-Date: 14 Jul 2022 22:18:15 EDT X-submission-address: compilers@iecc.com X-moderator-address: compilers-request@iecc.com X-FAQ-and-archives: http://compilers.iecc.com Xref: csiph.com comp.compilers:3118 On Wed, 13 Jul 2022 19:52:45 -0000 (UTC), antispam@math.uni.wroc.pl wrote: >Hmm, from flex manual: > >: -Ce, --ecs >: construct equivalence classes >: >: -Cm, --meta-ecs >: construct meta-equivalence classes > >If you want smaller tables use options above and flex DFA will >work on character classes. But note that Flex /may/ run considerably slower if you make heavy use of equivalence classes. IIRC, that results in (moral equivalent of) NFA rather than DFA. George [On modern computers it's hard to imagine a scanner so big that the space savings from those two options are worth it. 64K PDP-11 and all that. -John]