From: "Michael W. Ryder" <_mwryder@...> Date: 2007-09-05T16:30:08+09:00 Subject: Re: subject line M. Edward (Ed) Borasky wrote: > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA1 > > Bill Kelly wrote: >> From: "M. Edward (Ed) Borasky" >>> Which reminds me ... I keep meaning to ask ... how *did* regular >>> expressions morph from an undergraduate computer science concept into a >>> "language" that *every* working programmer is expected to be able to >>> read and write in his or her sleep? Let's debate *that*! ;) >> grep, sed, awk, . . . perl, ruby, . . . >> ? >> >> :) >> >> >> Regards, >> >> Bill >> >> >> >> > > Yes ... that part of it I know ... UNIX as a way for researchers to get > lots of work done with text files, "grep" standing for "Generalized > Regular Expression Processor", etc. The part I don't know is how it went > from Kleene, an obscure computational structure equivalent to finite > state machines, an exercise in undergraduate automata theory textbooks, > etc., to a practical tool like "grep", and I don't know why it "caught on". The first time I used them was in a mainframe editor that used a superset of them. You could go to the beginning of a file, skip 20 occurrences of a pattern, change the next 50 occurrences of a different pattern, etc. This was a major improvement when you had to edit a 10,000 line file on a mechanical tty. In today's multi-core, multi-GHz personal computers something like this would not be too noticeable time wise, but on a 60 cps tty the ability to do something like this was a huge time saver. > -----BEGIN PGP SIGNATURE----- > Version: GnuPG v1.4.7 (GNU/Linux) > Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org > > iD8DBQFG3iMf8fKMegVjSM8RArx/AKCqt2vruuQlnredgjsLf4Uhe2WywACgxhp3 > QjkcSZ99tPpyHdPcpLLS1T4= > =euON > -----END PGP SIGNATURE----- >