Path: csiph.com!weretis.net!feeder6.news.weretis.net!news.misty.com!news.iecc.com!.POSTED.news.iecc.com!nerds-end From: gah4 Newsgroups: comp.compilers Subject: Re: Why are ambiguous grammars usually a bad idea? Why are languages usually defined and implemented with ambiguous grammars? Date: Thu, 30 Dec 2021 13:40:32 -0800 (PST) Organization: Compilers Central Lines: 28 Sender: news@iecc.com Approved: comp.compilers@iecc.com Message-ID: <21-12-031@comp.compilers> References: <21-12-003@comp.compilers> <21-12-017@comp.compilers> <21-12-022@comp.compilers> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Injection-Info: gal.iecc.com; posting-host="news.iecc.com:2001:470:1f07:1126:0:676f:7373:6970"; logging-data="12374"; mail-complaints-to="abuse@iecc.com" Keywords: parse, optimize, design, comment Posted-Date: 30 Dec 2021 18:40:38 EST X-submission-address: compilers@iecc.com X-moderator-address: compilers-request@iecc.com X-FAQ-and-archives: http://compilers.iecc.com In-Reply-To: <21-12-022@comp.compilers> Xref: csiph.com comp.compilers:2781 On Wednesday, December 29, 2021 at 7:28:33 PM UTC-8, gah4 wrote: (snip, I wrote) > This reminds me of learning associativity of exponentiation (**) > in Fortran IV (I believe it isn't in the Fortran 66 standard) before I > learned it in algebra class. I suspect that there are others I learned > from programming before learning them in math class (snip) > [Fortran has always had ** exponentiation, starting with the original > version in 1956. It always bound tighter than +-*/ but wasn't > associative, A**B**C not allowed, -John] It was, at least, in Fortran IV for IBM 360/370: https://atariwiki.org/wiki/attach/Fortran/IBM_FORTRAN_IV-Language_1973.pdf My 8th grade graduation present was the above manual, though maybe one year earlier. I used to read IBM reference manuals like books, from start to finish. By the end of summer, I had run many Fortran programs. As well as I know it, IBM Fortran IV was the input to the 1966 standard, but not all features were included. It might also be that extensions were added later. [I used Fortran H on Princeston's 360/91 in a summer job I had in college in about 1973. -John]