Re: [Ocaml-lib-devel] XML Light

[Nicolas C. <war...@fr...>]

> > resulting library binary won't exceed few KB.
> > PXP have to go its own way, there is really enough space and need for
one
> > library like Xml Light, don't you think ?
>
> If you want my real opinion, after reading some of the Tim Bray
> discussions recently on the pros and cons of working with XML
>
> http://www.tbray.org/ongoing/When/200x/2003/03/16/XML-Prog
>
> I was looking forward to messing around with a regex style XML
> processor.  It looks much easier than any of the event, push,
> pull models of working with XML.
>
> Getting a Ocaml version of this would be cool and be a new
> direction in processing XML.

The OCaml pattern matching is enough for that, don't you think ?

while (<STDIN>) {
  next if (X<meta>X);
  if    (X<h1>|<h2>|<h3>|<h4>X)
  { $divert = 'head'; }
  elsif (X<img src="/^(.*\.jpg)$/i>X)
  { &proc_jpeg($1); }
  # and so on...
}


OCaml :

let process = function
    | Elements ("meta",_,_) -> ()
    | Elements ("h1",_,_) | Elements ("h2",_,_) | Elements ("h3",_,_) |
Elements ("h4",_,_)  -> divert := "head"
    | Elements ("img",attr,_) as x -> proc_jpeg (Xml.attrib x "src")
    | ... (* and so on *)
in
let rec walk = function
    | PCData _ -> ()
    | Elements (_,_,children) as x ->
        process x;
        List.iter walk children
in
walk (Xml.parse_in stdin)

Of course, this version is first reading all stdin and parsing it as a Xml
tree before processing, but I'm thinking right now of adding Lazy xml
processing to Xml Light so you parse only what you need. Others things
possible are to generate a MLI file from an DTD which will provide all types
and conversion functions from and to XML.

Nicolas Cannasse