Re: [Caml-list] ocamllex parametrized parse regexp

[luc.maranget@inria.fr (Luc Maranget)]

> Hi,
> 
> I try to use ocamllex like this (I want to have one of the parsing regexp  
> to be read from an external file) :
> 
> 
> {
>   open Printf;;
> 
> }
> let digit = ['0'-'9']
> 
> let mark = ...read in a file...
> 
> rule oaddress outcan = parse
>   | mark as bemark
>       {
>         printf "MARK(%s)" bemark;
>         oaddress outcan lexbuf
>       }
>   | _ as d
>       { printf "Unk[%c]\n" d;
>         oaddress outcan lexbuf
>       }
>   | eof
>       {
>         fprintf outcan "END";
>       }
> 
> Is it possible or useless to try somethink like that ?


ocamllex is a standard compiler, it compiles its input base.mll file into
a base.ml file that implements the lexer.

The language understood by ocamllex remains quite basic. As a consequence
there is no built-in support for what you want.
(Basically the 'let name = regexp' feature can be seen as simple macros).

However, nothing prevents you from generating the appropriate source
(.mll) files before you feed them into ocamllex.

-- Luc

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