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Parameterised lexer
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Date: -- (:)
From: Dario Teixeira <darioteixeira@y...>
Subject: Parameterised lexer
Hi,

Is it possible to write a ocamllex/ulex scanner where a regexp is a parameter
to the lexer function?  I'm looking for something like the (invalid) ulex
code below demonstrates ("param" is the parameter):

let regexp alpha = ['a'-'z' 'A'-'Z']
let regexp whitespace = [' ' '\t' '\n']
let regexp param1 = 'x'
let regexp param2 = 'y'
let regexp param3 = 'z'

let rec token param = lexer
        | param         ->      Printf.print "*";
                                token param lexbuf
        | alpha+        ->      Printf.printf "%s" (Ulexing.utf8_lexeme lexbuf);
                                token param lexbuf
        | whitespace+   ->      Printf.printf " ";
                                token param lexbuf
        | eof           ->      Printf.printf "EOF\n"

let main () =
        let lexbuf = Ulexing.from_utf8_channel stdin
        in token param1 lexbuf

let _ = Printexc.print main ()


Thanks in advance for your help!
Kind regards,
Dario Teixeira