Separation of Concerns (was Re: [xml-dev] The XML 1.1 Candidate Recommendation is published)

From: "Karl Waclawek" <>

> I am sure there will be (or are) generic libraries for that kind of
> Unicode processing. To me this looks as if there is no proper
> "separation of concerns", i.e. an XML processor should not concern
> itself with the issue of normalization.

Two comments

 1) Character, encoding and normalization issues are simply too
  hard for programmers to do.  XML provides the only real
  gateway where these things can be handled transparently,
  to shield the programmer from having to be aware of them,
  (to a great extent.)    It is a spurious "separation of concerns"
  to rely on layers that don't exist, IYSWIM.

 2) When I originally added normalization to opening XML
   files for a product, I found it slowed things down a lot
  (more than transcoding.)  But I soon found that just by
   adding a small test to see if my data was all < U+300
  (and therefore I didn't need to use the bulkier normalization
   routines) it becomes insignificant for most Western documents.
   So even though checking for normalization may add 
   slight complexity to parsers, it may not have any significant
   performance impact, except on documents containing characters
   where normalization may be important. 

Cheers
Rick Jelliffe