Comment author: Ted

The two characters that I have found for which the problem does not appear are these ones :

http://fr.wikipedia.org/wiki/%E1%BA%80 (does not exist in english wikipédia)
http://en.wikipedia.org/wiki/%E1%BA%BC

Comment author: @protz

From what OCaml prints, your Ô character uses two bytes, so I guess you're inputting utf-8. OCaml still lives in the former millenium and is not utf8-compatible, so I assume these uppercase and lowercase routines only work properly on latin1-encoded strings, unfortunately :).

I suggest you take a look at the Batteries project. It has a BatUTF8 module that provides some utf8 handling routines. If you need more advanced routines, Camomile is the Unicode library for OCaml.

Comment author: @protz

OCaml version 4.00.0

String.length "Ô";;

• : int = 2

(If you get the same results on your machine, then you're inputting utf8).

Comment author: Ted

It looks like I am inputting utf8 then. It does not surprise me that there is such encoding problems, but I really do not get why I got things like :

String.lowercase "é";;

• : string = "\227\169"

"é";;

• : string = "\195\169"

Could'nt String.lowercase just ignore accented letter characters when it does not recognize them ? As I do not need to actually print anything, the strange output does not bother me much, but the strange behaviour of String.lowercase does.

Comment author: @dbuenzli

But it does recognize them, the String module interprets strings as latin-1 encoded.

The behaviour is correct, in latin-1 \227\169 is the sequence 㩠which it correctly maps to \195\169 which is the sequence é.

Consult the table on this page http://en.wikipedia.org/wiki/ISO_8859-1

Comment author: Ted

Aah, I get it. Well, sorry for the "wrong" bug report, then.