Re: [boost] [Review] xpressive

From: Felipe Magno de Almeida (felipe.m.almeida_at_[hidden])
Date: 2005-09-15 02:02:27

Hi Christopher,

On 9/15/05, Christopher Kohlhoff <chris_at_[hidden]> wrote:

[snip]

> 
> >From my reading of the documentation, if I get a partial match and I
> want to continue to try for a full match I must buffer the entire data
> from the beginning of the partial match. This means that in the
> partial_regex_grep example it cannot find a substring match that is
> greater then 4096 characters long, because that is all the data it will
> buffer.

the same for spirit (If I'm wrong then I'm using it very inefficiently)

> 
> Furthermore, each time I want to retest the input against the
> expression it must process the whole input string again. This is not
> ideal from an efficiency point of view, since I could potentially
> receive input data one byte at a time.

indeed

> 
> What I want is a stateful regular expression-based decoder object
> (since in theory it's just a state machine and can remember its current
> state). I can feed it more input which will cause more state
> transitions, and it will tell me when it reaches a terminal state. I
> never have to buffer more input than the block just read because
> earlier input will have been fully consumed by the decoder.

IMO, it would be needed the possibility to have more than one grammar,
one for success and another for failure(Would be interesting to have
the possibility for more than two), until no-one has a match continue
to wait for more data...

> 
> As I said, this is an area I am very interested in exploring further
> when time permits (and not just in relation to regular expressions, but
> also things like Boost.Serialization), but that definitely belongs in
> its own thread.

IMO, it should be another library that should be able to interact with
AIO, spirit and xpressive. I already own some helper classes for
something like this, when they're called from the AIO components, they
forward to the grammars and verify success or failure, but they re-do
all the grammar processing again. I would be willing to volunteer to
help in a library like this, since I use it a lot for processing
protocols with AIO(sockets) and spirit and already have some code
writed. However, I dont have enough time to create such a library all
by myself.

> 
> Cheers,
> Chris

best regards,
-- 
   Felipe Magno de Almeida
Developer from synergy and Computer Science student from State
University of Campinas(UNICAMP).
Unicamp: http://www.ic.unicamp.br
Synergy: http://www.synergy.com.br
"There is no dark side of the moon really. Matter of fact it's all dark."