Re: Nothing at all to do with: Canonical equivalence in rendering: mandatory or recommended?

From: John Cowan (
Date: Wed Oct 15 2003 - 15:05:02 CST

Peter Kirk scripsit:

> You told me then that normalisation is not mandatory and so
> effectively only recommended. But if a reader is recommended to reject
> non-normalised input, the effect is that normalisation is mandated
> except for private communication between a group of cooperating
> processes.

The intention is that it's cheaper overall for the creator of the document
to normalize it once than for every receiver of the document to normalize
it, potentially many times over.

> So, while for example I may put a non-normalised text on my
> website, it would be rather pointless because any browser following
> recommendations would reject my page. Is that correct?

Yes, but I think it *very* unlikely that any general-use browser would
ever enforce that recommendation. In general, browsers are written to
accept as much as possible, at least in the HTML environment.
Even in a purely XML 1.1 world (which is unlikely to arrive for a number
of years!), I think that browsers would be built to perhaps warn the
user about non-normalized content, but by no means to reject it out of

The importance of normalization arises in machine-to-machine communication,
where the danger of being spoofed by non-normalized content that passes
unsubtly written filters is great. XML does not consider documents
equivalent merely because they are canonically equivalent; an element or
attribute name must be identical at the codepoint level to be correctly

> Am I in fact
> forced to work on the basis that normalisation is mandatory?


Not to perambulate                 John Cowan <>    
    the corridors        
during the hours of repose
    in the boots of ascension.       --Sign in Austrian ski-resort hotel  

This archive was generated by hypermail 2.1.5 : Thu Jan 18 2007 - 15:54:24 CST