Looking for an appropiate parser generator

[Iñaki Baz Castillo]

Hi, I'm new in this maillist so hello to all.

I want to do a SIP protocol parser in Ruby (SIP protocol is very similar to=
=20
HTTP) so I'm looking for the most appropiate parser in Ruby. Also, it's the=
=20
first time I try to do something like this so I need first lot of doc readi=
ng=20
(yacc, lex, LARL, LL, BNF...).

I'd just like to know with parser is a good option for my purpose since I'v=
e=20
found "too much" of them:

=2D rex
=2D ruby-lex
=2D racc
=2D ruby-yacc
=2D coco-rb
=2D TreeTop
=2D Ragel

=46or now I don't look for the fastest and most efficient parser, maybe jus=
t for=20
the easiest one. I will read those days about Yacc and Lex since I assume=20
they are the base of all of them, and I know that typically Yacc is used in=
=20
conjunction with Lex so:
If I choose Racc, will I need Rex?
If I choose Ruby-Yacc, will I need Ruby-Lex?
Note that I want to get Ruby code, not C, C++ or others.

My purpose is just receiving SIP requests (similar to HTTP requests) and pa=
rse=20
them (maybe into Ruby objects) to work with them (implement a SIP stack).

They are lots of options and I'm getting a little "lost" with so many doc t=
o=20
read. Any orientation please?

Thanks a lot and best regards.




=2D-=20
I=C3=B1aki Baz Castillo

 

[Eleanor McHugh]

Hi, I'm new in this maillist so hello to all.

I want to do a SIP protocol parser in Ruby (SIP protocol is very =20
similar to
HTTP) so I'm looking for the most appropiate parser in Ruby. Also, =20
it's the
first time I try to do something like this so I need first lot of =20
doc reading
(yacc, lex, LARL, LL, BNF...).

I'd just like to know with parser is a good option for my purpose =20
since I've
found "too much" of them:

- rex
- ruby-lex
- racc
- ruby-yacc
- coco-rb
- TreeTop
- Ragel

For now I don't look for the fastest and most efficient parser, =20
maybe just for
the easiest one. I will read those days about Yacc and Lex since I =20
assume
they are the base of all of them, and I know that typically Yacc is =20=

used in
conjunction with Lex so:
If I choose Racc, will I need Rex?
If I choose Ruby-Yacc, will I need Ruby-Lex?
Note that I want to get Ruby code, not C, C++ or others.

My purpose is just receiving SIP requests (similar to HTTP requests) =20=

and parse
them (maybe into Ruby objects) to work with them (implement a SIP =20
stack).

They are lots of options and I'm getting a little "lost" with so =20
many doc to
read. Any orientation please?

The SIP protocol is in principle simple enough that you could probably =20=

get by rolling your own custom parser by hand. My colleague =20
implemented a console-driven SIP stack this way and whilst the code is =20=

inefficient compared to a table-driven parser it's eminently more =20
readable.

However if you do want to go down the parser-generator route for =20
performance reasons then look at the Ragel parser in Mongrel as that's =20=

very efficient and highly conformant with the HTTP RFC specs (given =20
some of the boundary cases in SIP conformance is probably high on your =20=

list of priorities). As far as I'm aware Ragel produces parsers in C, =20=

but the Mongrel code will show you how to turn that into a Ruby native =20=

extension.


Ellie

Eleanor McHugh
Games With Brains

 

[Iñaki Baz Castillo]

El Domingo, 16 de Marzo de 2008, Eleanor McHugh escribi=F3:

The SIP protocol is in principle simple enough

opss, sure it's not simple at all, a lot of amiguations, each header has it=
s=20
own format, lots of extensions in lot of RFC's.... buff... simple?

that you could probably=20
get by rolling your own custom parser by hand.=20

It's what I'm doing for now but maybe it's better using an existing one. No=
=20
idea.

My colleague=20
implemented a console-driven SIP stack this way and whilst the code is
inefficient compared to a table-driven parser it's eminently more
readable.

However if you do want to go down the parser-generator route for
performance reasons then look at the Ragel parser in Mongrel as that's
very efficient and highly conformant with the HTTP RFC specs (given
some of the boundary cases in SIP conformance is probably high on your
list of priorities). As far as I'm aware Ragel produces parsers in C,
but the Mongrel code will show you how to turn that into a Ruby native
extension.

AFAIK Ragel can write to Ruby since verison 6.0:
http://www.devchix.com/2008/01/13/a-hello-world-for-ruby-on-ragel-60



Thanks a lot, I'll try Ragel.


=2D-=20
I=F1aki Baz Castillo

 

[Eleanor McHugh]

El Domingo, 16 de Marzo de 2008, Eleanor McHugh escribi=F3:


opss, sure it's not simple at all, a lot of amiguations, each header =20=

has its
own format, lots of extensions in lot of RFC's.... buff... simple?

I've probably spent too much time hanging around SIP obsessives

AFAIK Ragel can write to Ruby since verison 6.0:
http://www.devchix.com/2008/01/13/a-hello-world-for-ruby-on-ragel-60

Thanks a lot, I'll try Ragel.

I'll have to take a look at that myself.


Ellie

Eleanor McHugh
Games With Brains

 

[Daniel Brumbaugh Keeney]

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dG9wIHdpbnMgaW4gdGhhdCByZWdhcmQgYnkgYSBsb25nIHNob3QgdmVyc3VzCnJhY2MsIHJ1Ynkt
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[ThoML]

If you want easy, Treetop wins in that regard by a long shot versus

racc, ruby-yacc, or ragel.

In rubyquiz 155 (http://rubyquiz.com/quiz155.html), Grammar performed
pretty well. I haven't tried it out myself yet but the code looks
quite readable (see "some" submissions by E Mahurin).

Regards,
Thomas.