Character classification

Andrew Layman andrewl at
Wed Sep 3 22:39:59 BST 1997

JDK 1.1 is still broken for Unicode.  Take a look at the code in the
Microsoft XML Parser ( to see our

--Andrew Layman
   AndrewL at

> -----Original Message-----
> From:	Tim Bray [SMTP:tbray at]
> Sent:	Wednesday, September 03, 1997 12:51 PM
> To:	xml-dev at
> Subject:	Character classification
> I've been working on making Lark really do Unicode.  JDK 1.1 is
> supposed
> to have, unlike 1.0, a usable input method; thus the problem is to
> check,
> when you're reading a GI or Attribute name, whether the characters are
> legal namestart/name characters.
> It turns out to be quite a lot of work, so this is an offer to share.
> I wrote a program (based on Lark) that pulls the relevant character
> classes out of the XML spec, picks apart the markup, and writes
> another
> Java class that has some static arrays and offers two methods:
> package textuality.lark;
> public class CharClasses
> {
>  public static boolean isNameC(char c)
>  public static boolean isNameStart(char c)
> }
> It needs about 4k of tables (which it binary-searches); it might be
> faster
> with 128k of byte-addressable tables or 16K of bitmaps, neither of
> which
> would be hard to implement.
> (a) is this a waste of time, i.e. are there Unicode library calls that
>     do it?
> (b) if not, has everyone else already done this?
> (c) if not, if I'm going to publish this, is the API above OK?
> I've attached the current Java source file for those who find the 
> explanation above insufficiently clear.
> Cheers, Tim Bray
> tbray at +1-604-708-9592 <<
> File: >> 

xml-dev: A list for W3C XML Developers
Archived as:
To unsubscribe, send to majordomo at the following message;
unsubscribe xml-dev
List coordinator, Henry Rzepa (rzepa at

More information about the Xml-dev mailing list