On 09/12/2010 05:47, Dawid Toton wrote:
> I'm going to define a parser and a printer for a simple grammar.
> Is there a way to define both of them in a single construct using some
> existing OCaml tool?
>
> For example, I have a keyword "function". The usual parser would contain
> a mapping like:
> "function" -> `Function
> and the straightforward printer would do:
> `Function -> "function"
>
> What is the best way to combine these definitions, so that duplication
> would be minimized?
> To be precise, avoiding duplication is not exactly what I need. I'm
> looking for something that would prevent making inconsistent changes to
> the parser and the printer.

I'm writing a tool called Parsini which, maybe, does what you're looking 
for. Parsini stands either for "parsing is not interesting" (i.e.: let's 
have a tool which does it quickly for us and move on to interesting 
things such as code generation) or for "parser houdini" or something :p

 From a simple grammar, the tool :
- infers and produces an AST ;
- produces an ocamlyacc source ;
- produces an ocamllex source (optional - you can use your own lexer) ;
- produces a main file with :
   * functions to read your main entries easily from a channel, a file, 
a string...
   * functions to pretty-print your AST.
Your AST is pretty-printed with the Ocaml syntax, not the syntax of your 
own language, which I do not know how to do.

I have not released the tool yet, so nothing is official nor documented 
but you might want to take a look. License will be BSD. I've copied the 
darcs repository on my website :

http://romain.bardou.fr/parsini

So you should be able to download it easily with :

darcs get http://romain.bardou.fr/parsini

Have fun,

-- 
Romain Bardou