Re: How to construct a BNF for a language mechanically and incrementally?

[Peng Yu]

On Tue, Dec 29, 2009 at 11:17 PM, John Levine <address@hidden> wrote:
>>I just start reading the book "flex & bison Text Processing Tools" by
>>John Levine. Please excuse me if I ask some question that are
>>available somewhere in the book. When the grammar become huge, it
>>would be inconvenient put all BNFs in a single file. I'm wondering how
>>a huge grammar is handled in bison?
>
> Slowly.  Bison has no built in provision for handling multiple source
> files, but it's easy enough to use something like soelim in your
> Makefile to combine several files into one and hand it to bison.

I have never used soelim before. I have been looking for some
introductory material on it, but I don't find anything useful. (The
man page is too terse and hard for me to figure out how to use it if I
know nothing about it).

The following document seem contains nothing, either.

http://sunsite.ualberta.ca/Documentation/Gnu/groff-1.16/html_chapter/groff_toc.html#TOC126

Would you please provide me with some tutorial on soelim?

>>> For some languages, like Fortran, Bison/Flex are not a good at all.
>
> Scanning Fortran with flex would be a losing battle, but once you have
> a scanner, parsing it with bison isn't hard.  Here's a scanner and
> parser for most of Fortran 77 that I wrote 20 years ago:
>
> ftp://ftp.iecc.com/pub/file/ftn-grammar.gz
>
> R's,
> John
>