Comment author: administrator

Full_Name: Berke Durak
Version: 3.08.2

The fields pos_lnum, pos_bol and pos_fname are not computed (this is
acknowledges in the manual).

They would be really useful. Every time I write a parser, I have to write a
location module to store the byte offsets of line positions... Last time I
was
pleased to see that this had finally been implemented only to find out that
the
fields weren't computed.

But the fields have to be computed by the lexer, since it is the only part of
the
code that has a notion of lines. So it has to be done by user-written code.

-- Damien

Comment author: administrator

Can't do that in a general way -DD

Comment author: administrator

On Tue, Jan 18, 2005 at 03:43:46PM +0100, Damien Doligez wrote:

Full_Name: Berke Durak
Version: 3.08.2

The fields pos_lnum, pos_bol and pos_fname are not computed (this is
acknowledges in the manual).

They would be really useful. Every time I write a parser, I have to write a
location module to store the byte offsets of line positions... Last time I
was
pleased to see that this had finally been implemented only to find out that
the
fields weren't computed.

But the fields have to be computed by the lexer, since it is the only part of
the
code that has a notion of lines.

Yes.

So it has to be done by user-written code.

Why ? A Lexing.of_channel_with_lines, implemented as follows,
would be nice in the standard library.

let lexbuf_from_channel_with_lines p ic =
let x = ref 0 (* Byte count )
in
Lexing.from_function
(fun s n ->
let n = input ic s 0 n in
for i = 0 to n - 1 do
if s.[i] = '\n' then
( put offset etc. *)
done;
x := !x + n;
n)
;;

-- Damien

--
Berke Durak