# Looking for an appropiate parser generator **URL:** \ **Category:** Ruby\ **Created:** [March 16, 2008, 12:25am UTC](https://www.ruby-forum.com/t/looking-for-an-appropiate-parser-generator/132048 "2008-03-16T00:25:23Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![ISSSSaki\_Baz\_C](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/i/51bf81/32.png) [@ISSSSaki\_Baz\_C](https://www.ruby-forum.com/u/ISSSSaki_Baz_C)\ **Post date:** [March 16, 2008, 12:25am UTC](https://www.ruby-forum.com/t/looking-for-an-appropiate-parser-generator/132048/1 "2008-03-16T00:25:23Z")
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 HTTP) so I’m looking for the most appropiate parser in Ruby. Also, it’s the first time I try to do something like this so I need first lot of doc reading (yacc, lex, LARL, LL, BNF…). I’d just like to know with parser is a good option for my purpose 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, maybe just for the easiest one. I will read those days about Yacc and Lex since I assume they are the base of all of them, and I know that typically Yacc is 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) and parse 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 to read. Any orientation please? Thanks a lot and best regards. ---
**Author:** ![ISSSSaki\_Baz\_C](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/i/51bf81/32.png) [@ISSSSaki\_Baz\_C](https://www.ruby-forum.com/u/ISSSSaki_Baz_C)\ **Post date:** [March 16, 2008, 2:31am UTC](https://www.ruby-forum.com/t/looking-for-an-appropiate-parser-generator/132048/2 "2008-03-16T02:31:28Z")
On 15 Mar 2008, at 23:21, Iñaki Baz C. wrote: > I’d just like to know with parser is a good option for my purpose > > My purpose is just receiving SIP requests (similar to HTTP requests) > and parse > 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 to > read. Any orientation please? The SIP protocol is in principle simple enough that you could probably get by rolling your own custom parser by hand. My colleague 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. Ellie ## Eleanor McHugh Games With Brains raise ArgumentError unless @reality.responds\_to? :reason ---
**Author:** ![ISSSSaki\_Baz\_C](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/i/51bf81/32.png) [@ISSSSaki\_Baz\_C](https://www.ruby-forum.com/u/ISSSSaki_Baz_C)\ **Post date:** [March 16, 2008, 3:43am UTC](https://www.ruby-forum.com/t/looking-for-an-appropiate-parser-generator/132048/3 "2008-03-16T03:43:36Z")
El Domingo, 16 de Marzo de 2008, Eleanor McHugh escribió: > The SIP protocol is in principle simple enough opss, sure it’s not simple at all, a lot of amiguations, each header has its own format, lots of extensions in lot of RFC’s… buff… simple? > that you could probably > get by rolling your own custom parser by hand. > It’s what I’m doing for now but maybe it’s better using an existing one. > No > idea. > 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: [devchix.com at Directnic](http://www.devchix.com/2008/01/13/a-hello-world-for-ruby-on-ragel-60) Thanks a lot, I’ll try Ragel. ---
**Author:** ![ISSSSaki\_Baz\_C](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/i/51bf81/32.png) [@ISSSSaki\_Baz\_C](https://www.ruby-forum.com/u/ISSSSaki_Baz_C)\ **Post date:** [March 16, 2008, 7:01pm UTC](https://www.ruby-forum.com/t/looking-for-an-appropiate-parser-generator/132048/4 "2008-03-16T19:01:35Z")
On 16 Mar 2008, at 02:42, Iñaki Baz C. wrote: > El Domingo, 16 de Marzo de 2008, Eleanor McHugh escribió: > > > The SIP protocol is in principle simple enough > > opss, sure it’s not simple at all, a lot of amiguations, each header > 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: > [devchix.com at Directnic](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 raise ArgumentError unless @reality.responds\_to? :reason ---
**Author:** ![ISSSSaki\_Baz\_C](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/i/51bf81/32.png) [@ISSSSaki\_Baz\_C](https://www.ruby-forum.com/u/ISSSSaki_Baz_C)\ **Post date:** [March 17, 2008, 1:28am UTC](https://www.ruby-forum.com/t/looking-for-an-appropiate-parser-generator/132048/5 "2008-03-17T01:28:16Z")
On Sat, Mar 15, 2008 at 6:21 PM, Iñaki Baz C. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > For now I don’t look for the fastest and most efficient parser, maybe just for > the easiest one. If you want easy, Treetop wins in that regard by a long shot versus racc, ruby-yacc, or ragel. Daniel Brumbaugh K. ---
**Author:** ![ISSSSaki\_Baz\_C](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/i/51bf81/32.png) [@ISSSSaki\_Baz\_C](https://www.ruby-forum.com/u/ISSSSaki_Baz_C)\ **Post date:** [March 17, 2008, 6:36am UTC](https://www.ruby-forum.com/t/looking-for-an-appropiate-parser-generator/132048/6 "2008-03-17T06:36:08Z")
> If you want easy, Treetop wins in that regard by a long shot versus > racc, ruby-yacc, or ragel. In rubyquiz 155 ([Ruby Quiz - Parsing JSON (#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.