Re: Software based character UART using Yacc (Bison) grammar ...

[Hans Aberg]

You are welcome. You forgot to cc the Help-Bison list; it's important  
that other readers get to know the state of a problem.

On 29 Sep 2005, at 01:55, Jamie Risk wrote:

> Hans Aberg wrote:
>
>
> > On 28 Sep 2005, at 04:24, Jamie Risk wrote:
> >
> >
> > > I've been trying to develop a small software based character UART.
> > > Eight (8) bit characters have one start bit (a zero) one stop  
> > > bit  (a one) and one odd bit of parity.  Idle states are a one,  
> > > so  getting 100's of ones in a row is acceptable.  The  
> > > acceptable  format is:
> >
> >
> > Bison is not built for the kind of problem. You might be able to  
> > do  it with Flex. For example, you could have a loop scanning for  
> > the  first '0', and when it arrives, you set a start condition for  
> > a rule  picking down the next ten characters. If there is  
> > something wrong  with them, put them back, and rescan; otherwise  
> > output re character.
> >
> >   Hans Aberg
> Thanks.  You're absolutely right.  The problem was originally well  
> suited to Bison which eventually distilled down the problem I  
> presented - I never bothered to reevulate the tool during the  
> distallation.
>
> - Jamie