Re: bison version in graph output file

[Akim Demaille]

Le 2 mai 2010 à 02:55, Joel E. Denny a écrit :

>> also the graph title will appear in few types of dot
>> output, for example the ps output with 'dot -Tps' as:
> 
> I wasn't aware of that.  Good point.
> 
> What about something like
> 
>  "LALR(1) Automaton for parser.y"
> 
> where LALR(1) could also be IELR(1) or canonical LR(1)?

Better yet.

> I think we could potentially grow many pieces of information like this 
> (for example, whether it's LALR(1) and whether default reductions are 
> enabled), but how much should be on one line?  What about using something 
> like "grep -A3 Bison *.dot"?

Maybe we should use the fact that attributes are free, and it is not an error 
(at least with the tools I know) to have attributes that "don't make sense".  
Tools already tailored to parse Dot files would have access to Bison attributes 
for free, instead of having to learn how to parse our comments.  Say

graph "The title"
{
  graph [
          bisonVersion = "2.4.3",
          bisonGrammarFile = "parse-dot.y",
          bisonAutomatonType = "LALR(1)",
        ]
}

etc.  It would certainly make it easier to keep consistent the meta-data in all 
our outputs.

>> noticed there is no statement about the copyright status
>> of gcc and bison generated graph output files, assuming
>> it is "undefined" and maybe not good situation for the
>> fsf free software foundation.
> 
> I don't know, but I don't believe we've ever worried about that before.  
> Akim?

No idea here.  That would be a good place to use Dot comments :)