[Qemu-devel] Re: [PATCH 0/6]: QMP: Fix issues in parser/lexer

[Anthony Liguori]

On 05/20/2010 10:18 AM, Paolo Bonzini wrote:
> On 05/19/2010 11:43 PM, Anthony Liguori wrote:
> > > 4. Lexer expects a 'terminal' char to process a token
> > >
> > >     Which means clients must send a sort of end of line char, so 
> > > that we
> > >     process their input.
> > >
> > >     Maybe I'm missing something here, but I thought that the whole
> > >     point of writing our own parser was to avoid this.
> >
> > If the lexer gets:
> >
> > "abc"
> >
> > It has no way of knowing if that's a token or if we're going to get:
> >
> > "abcd"
>
> Only } and ] are valid characters at the end of a JSON object, and 
> neither requires lookahead.

Having look ahead operate differently for different states really 
complicates the lexer.  I don't see this as a big problem in practice.

Regards,

Anthony Liguori

> Paolo