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Re: "How to Compare URIs" update 3

From: Tim Bray <tbray@textuality.com>
Date: Fri, 21 Feb 2003 15:01:31 -0800
Message-ID: <3E56AFCB.6030509@textuality.com>
To: Martin Duerst <duerst@w3.org>
Cc: WWW-Tag <www-tag@w3.org>

Martin Duerst wrote:

> - The 'Status of this document' says 'This is the second draft'.
>   Guess this should be 'third'.

By the time I make this change, it'll be the fifth :)

> - The first sentence of the Introduction can be read two ways:
>   "Software is commonly required to compare two URIs."
>   Does this mean:
>     "Comparing URIs is rarely done by hand, software is commonly used to 
> do the job."
>   or:
>     "Software often has a need to compare two URIs."

Both.  I think it's fine.

> - Please include some examples for 'Simple String Comparison'

I have berated other people enough times over this issue that I can 
hardly push back, but really?  Presumably people know about simple 
string comparison...

> - I have to disagree that http://dir/a and http://dir/%61 can be
>   considered to be different. 
...
>   I therefore suggest that the section on %-escaping be the first
>   section of RFC2396-Sensitive Comparison, and that it nails down
>   that %-equivalence (e.g. ~ == %7E == %7e) is (as currently observed)
>   and be (to be specified by specifications) the minimal (baseline)
>   equivalence to be respected by resolution-related operations
>   (as opposed to namespace-like equivalences). (with the exception
>   of reserved characters)

Except for, in EBCDIC, %61 is '/', a reserved character; so on an EBCDIC 
computer, what you see on the screen as /dir/a and /dir/%61 reference 
different URIs.  And if you were writing EBCDIC software, you'd have to 
be careful.  Personally, if I were rewriting 2396 I would simply decree 
that all %-escaping be done on the UTF-8 mapping and only the UTF-8 
mapping, and be forbidden unless it's compulsory. But that's not what 
2396 currently says.

>   I'd be glad to help with some actual text.

Please. -Tim
Received on Friday, 21 February 2003 18:01:31 GMT

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