17 May
2020
17 May
'20
5:53 a.m.
Tony Finch wrote in
<alpine.DEB.2.20.2005142316170.3374(a)grey.csi.cam.ac.uk>:
|Larry McVoy <lm(a)mcvoy.com> wrote:
|>
|> It's got some perl goodness, regexps are part of the syntax, ....
|
|I got into Unix after perl and I've used it a lot. Back in the 1990s I saw
|Henry Spencer's joke that perl was the Swiss Army Chainsaw of Unix, as a
|riff on lex being its Swiss Army Knife. I came to appreciate lex
|regrettably late: lex makes it remarkably easy to chew through a huge pile
|of text and feed the pieces to some library code written in C. I've been
|using re2c recently (http://re2c.org/) which is differently weird than
|lex, though it still uses YY in all its variable names. It's remarkable
|how much newer lexer/parser generators can't escape from the user
|interface of lex/yacc. Another YY example: http://www.hwaci.com/sw/lemon/
P.S.: i really hate automated lexers. I never ever got used to
use them. For learning i once tried to use flex/bison, but
i failed really hard. I like that blood, sweat and tears thing,
and using a lexer seems so shattered, all the pieces. And i find
them really hard to read.
If you can deal with them they are surely a relief, especially in
rapidly moving syntax situations. But if i look at settled source
code which uses it, for example usr.sbin/ospfd/parse.y, or
usr.sbin/smtpd/parse.y, both of OpenBSD, then i feel lost and am
happy that i do not need to maintain that code.
--steffen
|
|Der Kragenbaer, The moon bear,
|der holt sich munter he cheerfully and one by one
|einen nach dem anderen runter wa.ks himself off
|(By Robert Gernhardt)