Re: [Caml-list] Case-insensitive lexing

[Jon Harrop <jon@ffconsultancy.com>]

On Friday 23 February 2007 15:32, Joel Reymont wrote:
> Is there a way to make a case-insensitive lexer with ocamllex?

Preprocess the character stream, making all chars lower case before they even 
reach ocamllex.

Take the existing definition of Lexing.from_channel:

let from_channel ic =
  from_function (fun buf n -> input ic buf 0 n)

and alter it to change the case of chars as they are read (off the top of my 
head):

let from_case_insensitive_channel ic =
  let aux buf n =
    let i = input ic buf 0 n in
    for i=0 to i-1 do
      buf.[i] <- Char.lowercase buf.[i]
    done;
    i in
  from_function aux

Now create your lexbuf using from_case_insensitive_channel.

-- 
Dr Jon D Harrop, Flying Frog Consultancy Ltd.
OCaml for Scientists
http://www.ffconsultancy.com/products/ocaml_for_scientists