Re: Using bison (or bisonc++) to create parser for command completion

[José Alburquerque]

Hans Aberg said the following:
> On 4 Feb 2009, at 03:40, José Alburquerque wrote:
>
> > Hi.  I'm not subscribed to this list, but I'm hoping someone here can 
> > still help me.  I'm attempting to develop a small front-end to 
> > dvdauthor  in C++ to logically create DVD's to be played in standard 
> > DVD players. I would like to include "command completion" 
> > functionality in an area of the GUI for accepting low level commands 
> > to the DVD player based on a very simple language, already specified 
> > for this purpose by the dvdauthor developers (if I'm not 
> > mistaken)[1].  All I'm really asking for, if possible, is 
> > clarification on whether bison can be used to create a parser for the 
> > simple language and then somehow use the parser to tell what might 
> > come after certain keywords.  If so, is it straight forward?  
> > Finally, I've looked a bit at bisonc++ and am wondering if it can be 
> > used instead of bison for the same purposes (I'd rather have C++ 
> > classes, if possible).  Please, any clarification would be greatly 
> > appreciated.
>
> You can use the .output file that Bison generates to get a set of 
> possible tokens for each state. The look at the top of the state stack 
> in the parser that Bison generates, and present that. Not in any 
> automated fashion, though, as far as I know.

I'm guessing that bisonc++ also generates a .output file.  Would you or 
anyone else know?

> One problem is that the LALR(1) parsing algorithm that Bison uses 
> makes state compaction which may admit some reductions before a state 
> where the error/lookahead tokens appears. So this method may note be 
> correct - strictly speaking, one should use LR(1). But the problem may 
> not be too severe.

Are there other tools that work with LR(1)?  Maybe I can look into those 
if they exist.  Thanks for your answers.  Really appreciate it.

>   Hans


--
José Alburquerque
address@hidden