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From Emmanuel Lécharny <>
Subject Re: [grammar] pure java syntax analyzer (this is not a compiler of compiler)
Date Tue, 17 Nov 2009 02:07:47 GMT
Gaël Lalire wrote:
> Hello,
Hi !
> Today if you want to do syntax analysis, you have to use a compiler of compiler (bison,
yacc, javaCC ...) which generates source code.
> After generation, you need to compile your generated source code and then you can parse
some input.
> I dislike this method because :
> - you need to learn a meta-language (the language which describe the grammar)
> - reusability of grammar is excluded
> - the grammar cannot be dynamic (self described)
> However I did not found any dynamical grammar analyzer so I decided to write it.
> I separate my project in 3 modules :
> - API : define Token, Terminal, Grammar, exceptions, ... ; A lexical analyzer have to
depends on this module to send terminals to the syntax analyzer
> - Impl : The analyzers (LR, LL, SLR, ...) and some calculation utilities.
> - SPI : This module provide user friendly abstract classes. For example, if you create
a grammar using this module there will be a type checking (generics) on non-terminals
> and its rules, so you will be sure that there will be no ClassCastException. It also
provide a easy way to create arithmetic expression (you just need to provide terminals, the
> will create the rules).
I checked the code base and there are interesting (though partial) good 
ideas there. I really like the approach, ie providing a way to define 
your grammar in Java. Make me think that at some point, it could be cool 
to use annotations to define the grammar ...
> Why donate to apache ?
> I hope that I'm not the only one interested by having a runtime grammar tool, and I hope
I could create a community on this project (because I'm alone).
> This isn't an easy domain, there is many things I do not know about compilation, so a
community could bring speeder or new implementations.
> Also apache is well-known in university, which could be interested on this project for
practical exercises.
As Gurkan stated, the very first step is to fill a proposal :
> Future tasks :
> - LL(*) to create (abstract LL exists and is untested)
> - LR(1+) to create (I need documentations)
> - LALR(*) to create (need documentations too)
> - SLR(2+) to create (need documentations always)
> - Naming issue (bad english, bad words ...)
> - Comments
> - Tutorial
> - Find a way to serialize the grammar's states (actions on terminal input maps) and restore
it with a simple bindings of terminals instead of grammar analyze.
> - Create bindings with a lexer (ORO ? JDK ?)
> - More reusable grammar part (boolean expression, sql parser, ...)
> - Parsing error management
> - Create a BNF to the SPI convertor
> - ...
> I join a source code to this mail.
> This is a maven2 / eclipse project [eclipse is not mandatory but the .project is provided]
> Now I need a champion (If I understand the mechanism : apache rule are not simple) to
integrate the project.
Apache rules are simple. It's just that they are formal. This is the key 
to get a successful project out of incubation : The ASF is not 
sourceForge, and we promote Community above Code : the project must 
remain alive even if you quit it.

Thanks !

cordialement, regards,
Emmanuel Lécharny

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