From: Brantley Coile <brantley@coraid.com>
To: Warner Losh <imp@bsdimp.com>
Cc: The Eunuchs Hysterical Society <tuhs@tuhs.org>
Subject: Re: [TUHS] v7 K&R C [really lexers]
Date: Sun, 17 May 2020 01:36:16 +0000 [thread overview]
Message-ID: <9C240181-E905-4DA0-8702-34A9201CA77A@coraid.com> (raw)
In-Reply-To: <CANCZdfp6KdSuEBhAay005Xc3pvw5oeGzHhyufY_xAfRT+UUE-Q@mail.gmail.com>
It looks like only grap and pic have mkfiles that invoke lex.
> On May 16, 2020, at 9:23 PM, Warner Losh <imp@bsdimp.com> wrote:
>
>
>
> On Sat, May 16, 2020, 6:05 PM Brantley Coile <brantley@coraid.com> wrote:
> “The asteroid to kill this dinosaur is still in orbit.“
> —- Plan 9 lex man page
>
> I always hand craft my lexers and use yacc to parse. Most code on plan 9 does that as well.
>
> Wow! That is the most awesome thing I've seen in a while....
>
> Warner
>
>
> Brantley
>
>
>> On May 16, 2020, at 8:00 PM, Jon Steinhart <jon@fourwinds.com> wrote:
>>
>> Steffen Nurpmeso writes:
>>> Tony Finch wrote in
>>> <alpine.DEB.2.20.2005142316170.3374@grey.csi.cam.ac.uk>:
>>> |Larry McVoy <lm@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
>>
>> Wow, I've had the opposite experience. I find lex/yacc/flex/bison really
>> easy to use. The issue, which I believe was covered in the early docs,
>> is that some languages are not designed with regularity in mind which makes
>> for ugly code. But to be fair, that code is at least as ugly with hand-crafted
>> code.
>>
>> I believe that the original wisecrack was directed towards FORTRAN. My ancient
>> experience was that it was using lex/yacc for HSPICE was not going to work so I
>> had to hand-craft code for that.
>>
>> Jon
next prev parent reply other threads:[~2020-05-17 1:36 UTC|newest]
Thread overview: 65+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-25 1:59 [TUHS] v7 K&R C Adam Thornton
2020-04-25 2:37 ` Charles Anthony
2020-04-25 2:47 ` Adam Thornton
2020-04-25 2:51 ` Rob Pike
2020-04-25 2:54 ` Rob Pike
2020-04-25 3:04 ` Larry McVoy
2020-04-25 3:30 ` Clem Cole
2020-04-25 3:43 ` Larry McVoy
2020-04-25 3:54 ` Jon Steinhart
2020-04-25 11:44 ` Michael Kjörling
2020-04-25 13:17 ` Dan Cross
2020-05-11 0:28 ` scj
2020-05-11 0:32 ` Rob Pike
2020-05-11 0:57 ` Larry McVoy
2020-05-11 17:32 ` Greg A. Woods
2020-05-11 18:25 ` Paul Winalski
2020-05-11 18:37 ` Clem Cole
2020-05-11 19:12 ` Paul Winalski
2020-05-11 19:57 ` joe mcguckin
2020-05-11 20:25 ` Larry McVoy
2020-05-12 17:23 ` Paul Winalski
2020-05-12 17:35 ` ron
2020-05-12 17:42 ` Larry McVoy
2020-05-12 18:36 ` Paul Winalski
2020-05-13 23:36 ` Dave Horsfall
2020-05-14 0:42 ` John P. Linderman
2020-05-14 2:44 ` Rich Morin
2020-05-14 3:09 ` Charles Anthony
2020-05-14 12:27 ` ron
2020-05-14 12:27 ` ron
2020-05-14 12:27 ` ron
2020-05-14 7:38 ` Dave Horsfall
2020-05-14 12:25 ` ron
2020-05-14 17:13 ` Paul Winalski
2020-05-14 17:21 ` Larry McVoy
2020-05-17 16:34 ` Derek Fawcus
2020-05-14 4:21 ` Greg A. Woods
2020-05-14 4:40 ` Warner Losh
2020-05-14 17:32 ` Larry McVoy
2020-05-14 22:32 ` Tony Finch
2020-05-16 23:53 ` Steffen Nurpmeso
2020-05-16 23:59 ` [TUHS] v7 K&R C [really lexers] Jon Steinhart
2020-05-17 0:04 ` Brantley Coile
2020-05-17 1:23 ` Warner Losh
2020-05-17 1:36 ` Brantley Coile [this message]
2020-06-13 21:24 ` scj
2020-06-14 8:47 ` arnold
2020-06-14 12:52 ` Richard Salz
2020-06-14 14:03 ` Ralph Corderoy
2020-06-14 14:26 ` arnold
2020-06-14 14:48 ` Ralph Corderoy
2020-06-15 1:12 ` Warren Toomey
2020-06-15 1:29 ` Warren Toomey
2020-06-15 6:06 ` arnold
2020-05-17 16:31 ` Paul Winalski
2020-05-17 0:35 ` [TUHS] v7 K&R C Larry McVoy
2020-05-11 18:37 ` Larry McVoy
2020-05-11 2:08 ` Lawrence Stewart
2020-05-11 11:36 ` Michael Kjörling
2020-04-25 3:37 ` Dave Horsfall
2020-04-27 13:19 ` Tony Finch
2020-04-25 2:50 ` Adam Thornton
2020-04-25 5:59 ` Lars Brinkhoff
2020-05-17 2:07 [TUHS] v7 K&R C [really lexers] Nelson H. F. Beebe
2020-06-14 13:55 Doug McIlroy
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