Re: Python Front-end to GCC

Date	2013-10-22 11:46 -0400
From	Ned Batchelder <ned@nedbatchelder.com>
Subject	Re: Python Front-end to GCC
References	(4 earlier) <mailman.1329.1382396650.18130.python-list@python.org> <m2haca2cjv.fsf@cochabamba.vanoostrum.org> <CAMjeLr9p9bE9g0PSAQN5_H0uQjOuBaq+_4Mj43Y3LCLNEY8n2A@mail.gmail.com> <l44vhp$f51$1@ger.gmane.org> <CAMjeLr-shQcviRmfAX8xTJkC9qS2hPZC-jZHUX4Rp++hgu5Gog@mail.gmail.com>
Newsgroups	comp.lang.python
Message-ID	<mailman.1357.1382456781.18130.python-list@python.org> (permalink)

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On 10/22/13 11:04 AM, Mark Janssen wrote:
> I love it.  Watch this...
>
> [context]
>>>> A language specification in BNF is just syntax. It doesn't say anything
>>>> about semantics. So how could this be used to produce executable C code
>>>> for a program? BNF is used to produce parsers. But a parser isn't
>>>> sufficient.
>>> A C program is just syntax also.  How does the compiler generate
>>> executable machine code?  Extrapolate into a Python front-end to C.
> [Dave Angel responds:]
>> Did you even read the paragraph you quoted above?  The BNF specification
>> does NOT completely describe a language, it only defines its syntax.
> [Steven D'Aprano responds:]
>> Like every other language, C programs are certainly not *just* syntax.
>> Here is some syntax:
>>
>> &foo bar^ :=
> Now, I don't know where y'all were taught Computer Science, but BNF
> specifies not only syntax (which would be the *tokens* of a language),
> but also its *grammar*;  how syntax relates to linguistic categories
> like keywords, and tokens relate to each other.

Mark, you had expressed interest in "an app that will take a language 
specification in BNF (complete with keywords and all) and output C code 
which is then compiled to an executable".   I'm interested in how that 
app might work.

Here's a BNF for a (very!) simple language:

     <program> ::= <number> <op> <number>
     <op> ::=  "*!?" | "--+" | "..:"

That means these are three valid programs:

     123 *!? 456
     2 --+ 2
     1001 ..: 4

What will the app output as C code for each of these?

>
> Dave is claiming that BNF only defines the syntax of a language, but
> then Stephen goes on to supply some syntax that a BNF specification of
> the language would not allow (even though Steven calls it "syntax"
> which is what BNF in Dave's claim parses).
>
> So which of you is confused?  I ask that in the inclusive (not
> exclusive OR) sense.... ;^)  <-- face says "both".

Could you please be less snarky?  We're trying to communicate here, and 
it is not at all clear yet who is confused and who is not.  If you are 
interested in discussing technical topics, then discuss them.

--Ned.

>
> Mark Janssen
> Tacoma, Washington.

Thread

Python Front-end to GCC Philip Herron <herron.philip@googlemail.com> - 2013-10-20 10:56 -0700
  Re: Python Front-end to GCC victorgarcianet@gmail.com - 2013-10-20 15:10 -0700
    Re: Python Front-end to GCC John Nagle <nagle@animats.com> - 2013-10-22 23:48 -0700
      Re: Python Front-end to GCC Philip Herron <herron.philip@googlemail.com> - 2013-10-23 00:25 -0700
        Re: Python Front-end to GCC Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-10-23 09:42 +0100
        Re: Python Front-end to GCC John Nagle <nagle@animats.com> - 2013-10-23 13:51 -0700
  Re: Python Front-end to GCC Mark Janssen <dreamingforward@gmail.com> - 2013-10-20 20:35 -0700
    Re: Python Front-end to GCC Steven D'Aprano <steve@pearwood.info> - 2013-10-21 07:46 +0000
      Re: Python Front-end to GCC Oscar Benjamin <oscar.j.benjamin@gmail.com> - 2013-10-21 10:55 +0100
        Re: Python Front-end to GCC Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-10-21 23:41 +0000
          Re: Python Front-end to GCC Oscar Benjamin <oscar.j.benjamin@gmail.com> - 2013-10-22 10:14 +0100
            Re: Python Front-end to GCC Philip Herron <herron.philip@googlemail.com> - 2013-10-22 02:32 -0700
            Re: Python Front-end to GCC Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-10-22 12:00 +0000
              Re: Python Front-end to GCC Chris Angelico <rosuav@gmail.com> - 2013-10-22 23:20 +1100
                Re: Python Front-end to GCC Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-10-22 17:27 +0000
                Re: Python Front-end to GCC Chris Angelico <rosuav@gmail.com> - 2013-10-23 08:43 +1100
              Re: Python Front-end to GCC Dave Angel <davea@davea.name> - 2013-10-22 14:04 +0000
                Re: Python Front-end to GCC Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-10-22 15:22 +0000
                Re: Python Front-end to GCC Grant Edwards <invalid@invalid.invalid> - 2013-10-22 15:39 +0000
                Re: Python Front-end to GCC Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-10-22 16:40 +0000
                Re: Python Front-end to GCC Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-10-22 17:50 +0100
                Re: Python Front-end to GCC Chris Kaynor <ckaynor@zindagigames.com> - 2013-10-22 09:52 -0700
                Re: Python Front-end to GCC Frank Miles <fpm@u.washington.edu> - 2013-10-22 16:53 +0000
                Re: Python Front-end to GCC Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-10-22 17:23 +0000
                Re: Python Front-end to GCC Chris Kaynor <ckaynor@zindagigames.com> - 2013-10-22 10:35 -0700
                Re: Python Front-end to GCC Neil Cerutti <neilc@norwich.edu> - 2013-10-22 17:37 +0000
                Re: Python Front-end to GCC Oscar Benjamin <oscar.j.benjamin@gmail.com> - 2013-10-22 18:37 +0100
                Re: Python Front-end to GCC MRAB <python@mrabarnett.plus.com> - 2013-10-22 18:42 +0100
                Re: Python Front-end to GCC Grant Edwards <invalid@invalid.invalid> - 2013-10-22 18:49 +0000
                Re: Python Front-end to GCC Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-10-25 04:40 +0100
                Re: Python Front-end to GCC Mark Janssen <dreamingforward@gmail.com> - 2013-10-25 04:55 -0700
                Re: Python Front-end to GCC Dan Sommers <dan@tombstonezero.net> - 2013-10-25 12:55 +0000
                Re: Python Front-end to GCC Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-10-25 15:18 +0100
                Re: Python Front-end to GCC Ned Batchelder <ned@nedbatchelder.com> - 2013-10-25 10:35 -0400
                Re: Python Front-end to GCC Mark Janssen <dreamingforward@gmail.com> - 2013-10-25 11:26 -0700
                Re: Python Front-end to GCC Grant Edwards <invalid@invalid.invalid> - 2013-10-25 19:06 +0000
                Re: Python Front-end to GCC Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-10-25 19:40 +0100
                Re: Python Front-end to GCC Mark Janssen <dreamingforward@gmail.com> - 2013-10-25 11:45 -0700
                Re: Python Front-end to GCC rusi <rustompmody@gmail.com> - 2013-10-25 11:59 -0700
                Re: Python Front-end to GCC Mark Janssen <dreamingforward@gmail.com> - 2013-10-25 12:09 -0700
                Re: Python Front-end to GCC rusi <rustompmody@gmail.com> - 2013-10-25 12:15 -0700
                Re: Python Front-end to GCC Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-10-25 20:02 +0100
                Re: Python Front-end to GCC Mark Janssen <dreamingforward@gmail.com> - 2013-10-25 12:18 -0700
                Re: Python Front-end to GCC John Nagle <nagle@animats.com> - 2013-10-26 14:31 -0700
                Re: Python Front-end to GCC Mark Janssen <dreamingforward@gmail.com> - 2013-10-26 15:10 -0700
                Re: Python Front-end to GCC Mark Janssen <dreamingforward@gmail.com> - 2013-10-27 15:14 -0700
                Re: Python Front-end to GCC rusi <rustompmody@gmail.com> - 2013-10-27 19:15 -0700
                Re: Python Front-end to GCC Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-10-28 08:44 +0000
                Re: Python Front-end to GCC rusi <rustompmody@gmail.com> - 2013-10-28 02:31 -0700
                Re: Python Front-end to GCC Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-10-25 20:36 +0100
                Re: Python Front-end to GCC Mark Janssen <dreamingforward@gmail.com> - 2013-10-25 12:49 -0700
                Re: Python Front-end to GCC Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-10-25 21:14 +0100
                Re: Python Front-end to GCC Tim Delaney <timothy.c.delaney@gmail.com> - 2013-10-26 07:11 +1100
                Re: Python Front-end to GCC Mark Janssen <dreamingforward@gmail.com> - 2013-10-25 13:29 -0700
                Re: Python Front-end to GCC Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-10-25 21:36 +0100
                Re: Python Front-end to GCC Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-10-26 02:42 +0000
                Re: Python Front-end to GCC Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-10-25 21:44 +0100
                Re: Python Front-end to GCC Tim Delaney <timothy.c.delaney@gmail.com> - 2013-10-26 07:48 +1100
                Re: Python Front-end to GCC Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-10-25 21:56 +0100
                Re: Python Front-end to GCC Mark Janssen <dreamingforward@gmail.com> - 2013-10-25 14:02 -0700
                Re: Python Front-end to GCC Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-10-25 22:11 +0100
                Re: Python Front-end to GCC Mark Janssen <dreamingforward@gmail.com> - 2013-10-25 14:37 -0700
                Re: Python Front-end to GCC Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-10-25 22:56 +0100
                Re: Python Front-end to GCC Chris Angelico <rosuav@gmail.com> - 2013-10-26 13:36 +1100
                Re: Python Front-end to GCC Neil Cerutti <neilc@norwich.edu> - 2013-10-22 17:15 +0000
                Re: Python Front-end to GCC Grant Edwards <invalid@invalid.invalid> - 2013-10-22 18:58 +0000
                Re: Python Front-end to GCC Grant Edwards <invalid@invalid.invalid> - 2013-10-22 20:26 +0000
                Re: Python Front-end to GCC Grant Edwards <invalid@invalid.invalid> - 2013-10-22 15:36 +0000
              Re: Python Front-end to GCC Oscar Benjamin <oscar.j.benjamin@gmail.com> - 2013-10-22 15:15 +0100
      Re: Python Front-end to GCC Mark Janssen <dreamingforward@gmail.com> - 2013-10-21 13:14 -0700
      Re: Python Front-end to GCC Ned Batchelder <ned@nedbatchelder.com> - 2013-10-21 16:29 -0400
        Re: Python Front-end to GCC rusi <rustompmody@gmail.com> - 2013-10-21 20:40 -0700
  Re: Python Front-end to GCC Philip Herron <herron.philip@googlemail.com> - 2013-10-21 04:08 -0700
    Re: Python Front-end to GCC Mark Janssen <dreamingforward@gmail.com> - 2013-10-21 13:26 -0700
      Re: Python Front-end to GCC Philip Herron <herron.philip@googlemail.com> - 2013-10-21 14:03 -0700
        Re: Python Front-end to GCC Mark Janssen <dreamingforward@gmail.com> - 2013-10-21 16:04 -0700
          Re: Python Front-end to GCC Piet van Oostrum <piet@vanoostrum.org> - 2013-10-21 23:45 -0400
            Re: Python Front-end to GCC Mark Janssen <dreamingforward@gmail.com> - 2013-10-21 21:24 -0700
              Re: Python Front-end to GCC Steven D'Aprano <steve@pearwood.info> - 2013-10-22 05:25 +0000
            Re: Python Front-end to GCC Dave Angel <davea@davea.name> - 2013-10-22 04:39 +0000
            Re: Python Front-end to GCC Mark Janssen <dreamingforward@gmail.com> - 2013-10-22 08:04 -0700
              Re: Python Front-end to GCC Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-10-22 17:09 +0000
              Re: Python Front-end to GCC Piet van Oostrum <piet@vanoostrum.org> - 2013-10-22 13:20 -0400
            Re: Python Front-end to GCC Ned Batchelder <ned@nedbatchelder.com> - 2013-10-22 11:46 -0400
            Re: Python Front-end to GCC Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-10-22 16:52 +0100
            Re: Python Front-end to GCC Benjamin Kaplan <benjamin.kaplan@case.edu> - 2013-10-22 09:03 -0700
            Re: Python Front-end to GCC Mark Janssen <dreamingforward@gmail.com> - 2013-10-22 10:50 -0700
              Re: Python Front-end to GCC rusi <rustompmody@gmail.com> - 2013-10-22 11:11 -0700
              Re: Python Front-end to GCC Neil Cerutti <neilc@norwich.edu> - 2013-10-22 18:18 +0000
                Re: Python Front-end to GCC Piet van Oostrum <piet@vanoostrum.org> - 2013-10-22 15:20 -0400
                Re: Python Front-end to GCC Neil Cerutti <neilc@norwich.edu> - 2013-10-22 19:27 +0000
                Re: Python Front-end to GCC Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-10-22 20:38 +0100
                Re: Python Front-end to GCC Neil Cerutti <neilc@norwich.edu> - 2013-10-22 20:00 +0000
                Re: Python Front-end to GCC Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-10-22 20:32 +0100
            Re: Python Front-end to GCC Skip Montanaro <skip@pobox.com> - 2013-10-22 13:08 -0500
            Re: Python Front-end to GCC MRAB <python@mrabarnett.plus.com> - 2013-10-22 19:16 +0100
            Re: Python Front-end to GCC Mark Janssen <dreamingforward@gmail.com> - 2013-10-22 11:16 -0700
            Re: Python Front-end to GCC Mark Janssen <dreamingforward@gmail.com> - 2013-10-22 11:22 -0700
            Re: Python Front-end to GCC Mark Janssen <dreamingforward@gmail.com> - 2013-10-22 11:28 -0700
              Re: Python Front-end to GCC Piet van Oostrum <piet@vanoostrum.org> - 2013-10-22 18:11 -0400
                Re: Python Front-end to GCC Chris Angelico <rosuav@gmail.com> - 2013-10-23 17:28 +1100
              Re: Python Front-end to GCC Grant Edwards <invalid@invalid.invalid> - 2013-10-22 22:47 +0000
            Re: Python Front-end to GCC Ned Batchelder <ned@nedbatchelder.com> - 2013-10-22 14:23 -0400
              Re: Python Front-end to GCC rusi <rustompmody@gmail.com> - 2013-10-22 11:40 -0700
                Re: Python Front-end to GCC Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-10-22 19:58 +0100
            Re: Python Front-end to GCC Ned Batchelder <ned@nedbatchelder.com> - 2013-10-22 14:40 -0400
              Re: Python Front-end to GCC alex23 <wuwei23@gmail.com> - 2013-10-23 11:36 +1000
                Re: Python Front-end to GCC rusi <rustompmody@gmail.com> - 2013-10-22 21:04 -0700
                Re: Python Front-end to GCC Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-10-23 07:06 +0100
            Re: Python Front-end to GCC MRAB <python@mrabarnett.plus.com> - 2013-10-22 19:47 +0100
            Re: Python Front-end to GCC Ned Batchelder <ned@nedbatchelder.com> - 2013-10-22 13:56 -0400
            Re: Python Front-end to GCC Michael Torrie <torriem@gmail.com> - 2013-10-22 22:05 -0600
            Re: Python Front-end to GCC Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-10-23 07:13 +0100
            Re: Python Front-end to GCC Mark Janssen <dreamingforward@gmail.com> - 2013-10-26 14:25 -0700
            Re: Python Front-end to GCC Mark Janssen <dreamingforward@gmail.com> - 2013-10-26 14:33 -0700
            Re: Python Front-end to GCC Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-10-26 22:38 +0100
            Re: Python Front-end to GCC Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-10-26 22:35 +0100
    Re: Python Front-end to GCC Antoine Pitrou <solipsis@pitrou.net> - 2013-10-22 08:55 +0000
      Re: Python Front-end to GCC Philip Herron <herron.philip@googlemail.com> - 2013-10-22 02:08 -0700
      Re: Python Front-end to GCC Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-10-22 10:10 +0000
        Re: Python Front-end to GCC Antoine Pitrou <solipsis@pitrou.net> - 2013-10-22 15:51 +0000
    Re: Python Front-end to GCC Stefan Behnel <stefan_ml@behnel.de> - 2013-10-24 08:47 +0200
  Re: Python Front-end to GCC xDog Walker <thudfoo@gmail.com> - 2013-10-25 14:49 -0700

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