Re: Lilypond BNF

[Han-Wen Nienhuys]

Carl Sorensen wrote:
> Almost a year ago, Pedro Kroger was working on a bnf description of
> lilypond. (see  http://lists.gnu.org/archive/html/lilypond-
> devel/2004-10/msg00074.html).  Han-Wen suggested hacking Bison so that
> it would produce the BNF directly from the .yy file.
>
> I went a different direction, and produced a python script that ignores
> all the C++ stuff in parser.yy, resulting in a BNF description of
> lilypond that is generated directly from the parser.
>
> I've attached the script (yy2bnf.py), along with the result of running
> the script on the current CVS version of parser.yy (lilypond.bnf).
>
> I'd like to suggest that lilypond.bnf be added to the documentation, to
> be automatically generated as part of the make process, using yy2bnf.py.

That would be cool,  but just dumping a BNF somewhere is a bit 
half-baked. Wouldn't it be better to make a "literate Yacc", where we 
intersperse explanations of the grammar (in texinfo format, so it can be 
integrated with the program reference manual) with the BNF itself? Also, 
a couple of nitpicks

 * BNF usually uses a slightly different syntax

  <nonterminal> ::=  <nt1> <nt2>

I believe. But frankly, I don't care about

 * The current script doesn't strip /* */ comments.


--
 Han-Wen Nienhuys - address@hidden - http://www.xs4all.nl/~hanwen