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RE: [Summary] UTF-8 Question: e with acute accent should requ

• From: "Alessandro Triglia" <sandro@m...>
• To: "'Costello, Roger L.'" <costello@m...>,<xml-dev@l...>
• Date: Fri, 28 Sep 2007 14:23:06 -0400

Hi Roger,

It is not correct to say that a Unicode character can be either an "ASCII
character" or a "non-ASCII character".  It is better to say that some
Unicode characters (those with codes below 128) have a corresponding
character in ASCII.

For example, your sentence "Most of its characters are ASCII, but there is
one non-ASCII character, the é character" is not correct.  A more precise
statement would be, "Most of its characters have a corresponding character
in the ASCII character set, but there is one character, the é character
(officially named "LATIN SMALL LETTER E WITH ACUTE", code 233), which has no
corresponding character in ASCII."

Elsewhere, when you say something like, "In UTF-8 all ASCII characters are
encoded using one byte", a more correct formulation might be, "In UTF-8 all
Unicode characters with codes below 128 are encoded in one byte.  Each of
those Unicode characters has a corresponding character in the ASCII
character set, and the encoding of that ASCII character (in ASCII) is
identical to the encoding of the Unicode character in UTF-8."  (Is this too
verbose perhaps?)

(So an ASCII character string, encoded, can be decoded as if it were a
Unicode character string encoded in UTF-8, and the meaning will be the same.
The other way around is generally not possible, as there may be byte values
above 127 that are not legal encodings of any ASCII characters.)

Alessandro

 

> -----Original Message-----
> From: Costello, Roger L. [mailto:costello@m...] 
> Sent: Friday, September 28, 2007 13:42
> To: xml-dev@l...
> Subject:  [Summary] UTF-8 Question: e with acute 
> accent should require two bytes, right?
> 
> Hi Folks,
> 
> Once again, outstanding information!
> 
> I have summarized at least part of the discussions:
> 
> http://www.xfront.com/encoding-example/
> 
> Comments always welcome.
> 
> Thanks!
> 
> /Roger
> 
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• Follow-Ups:
  • RE: [Summary] UTF-8 Question: e with acute accent should require two bytes, right?
    • From: "Michael Kay" <mike@s...>
  • Re: [Summary] UTF-8 Question: e with acute accent should require two bytes, right?
    • From: richard@i... (Richard Tobin)

• References:
  • UTF-8 Question: e with acute accent should require two bytes, right?
    • From: "Costello, Roger L." <costello@m...>
  • [Summary] UTF-8 Question: e with acute accent should require two bytes, right?
    • From: "Costello, Roger L." <costello@m...>