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Parse-RecDescent (1.94)

Parse::RecDescent used to be my second favourite module for parsing.
I like the powerful directives that make parsing much easier.

However there are three considerations where I feel Parse::Yapp is preferable:

- In RD is more difficult to deal with left recursive grammars. Usually you have to transform the "natural rules"

- Performance

- In RD, the language described by the grammar depends on the order of the rules. But probably this is more a question of taste than a drawback.

This is why Parse::Yapp was my favourite module for parsing
even if it lacks most of the beautiful features provided by Parse::RecDescent.

For these reasons I wrote an extension of Parse::Yapp named 'Parse::Eyapp'. Any program that runs on Parse::Yapp works without changing a comma on Parse::Eyapp.

Parse::Eyapp provides extensions similar to the ones you can find in Parse::RecDescent. For example, using the directive %defaultaction works as RD "autoactions".
The directive %tree is similar to <autotree>, etc.

I tried to merge the best of Yapp and RecDescent
and added a few extensions. Among others:
translations schemes and a language for the manipulation of abstract syntax trees.

If you like Parse::RecDescent, give it a try to Parse::Eyapp.

casiano - 2007-09-26 10:14:10
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Parse-RecDescent (1.94)

Easy to use, very flexible, very powerful, well-documented and venerable, Parse::RecDescent is a very good module for parsing any text that could be described by a grammar. Compared to Parse::Yapp, Perl-byacc, this one definitely wins hands down in all those aspects. The only caveat is the speed of the module when dealing with long input strings - its processing increases polynomially to string length (nearly O(n3) in benchmark). I made a detailed comparison, usage example of Parse::RecDescent, Parse::Yapp, and Perl-byacc during my Entrez Gene parser project at http://sourceforge.net/docman/display_doc.php?docid=27420&group_id=133629

This module is best for novice users, complex (context-sensitive or dynamic) grammars, or any situation where input is short or performance is no issue.

Mingyi Liu - 2005-03-15 14:10:46
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Parse-RecDescent (1.94)

I used this module to generate a parser for input files for the CADENCE SPECTRE simulator, and generate an XML DOM tree as output.

The parser I obtained is somewhat slow, but OK it does the job. I did not yet manage to use the 'warning messages' properly.

Renaud GILLON - 2004-08-17 13:03:17
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Parse-RecDescent (1.94)

Clearly one of my favourite modules. I do not find it ease to use nor can I make any statement about the quality of the interface. But I am absolutedly willing to accept, that this is because of the sheer complexity of the functionality this module provides.

I would not hesitate to give it a straight 5 overall rating, if it
was not so slow (execution speed of the grammars).

Richard Jelinek - 2004-06-01 09:18:23
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Parse-RecDescent (1.94)

Really great module.
When I tried using it, I realized that this module wiser than me, because it is capable accomplishing tasks that I can not do :)
Also afetr my PocketPC could easily run it, I got much more respect to my WinCE device :)
Also perlmonks.org community loves this module and find Parse::RecDescent questions very interesting to investigate and answer.

Vadim Konovalov - 2003-08-20 07:08:53
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Parse-RecDescent (1.94)

Learning Parse::RecDescent will make you smarter, and it might even help you get your job done. The documentation is fairly good, but I still needed to crack my copy of "lex & yacc" a few times while using it. The only major drawback of this module is its performance. It's probably the slowest module I've used since Date::Manip!

Sam Tregar - 2003-08-18 15:56:41
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Parse-RecDescent (1.94)

Parse::RecDescent is a great module.

It's saved me a lot of time when writing the parser for the Math::Symbolic module. In fact, I doubt there would be a parser for the Math::Symbolic module if there hadn't been Parse::RecDescent to do the difficult work for me.

Writing P::RD grammars needs a bit of time to get accustomed to if you know yacc, but once you get the hang of it, it's not too difficult.

The one main gripe I have with this module is its speed. Compiling parsers takes forever. (As of version 0.112, the Math::Symbolic parser took about a second to compile on my 2GHz machine!) Parsing isn't blazingly fast either. Especially with long input strings.

Steffen M�ller - 2003-08-17 03:55:35
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Parse-RecDescent (1.94)

Great module, except for speed on large target strings (known issue). To be fixed "next christmas".

Randal L. Schwartz - 2003-08-13 15:03:52
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