David Carlisle wrote:
>> 1. Why does XML not support many of the US-ASCII characters?
>>
> Because it's a textual format and code points like
> U+0017 END OF TRANSMISSION BLOCK
> don't really belong in text.
Not everyone agrees with that point of view. For example, RFC 5322 [1], Internet Message Format, is for *text* document and it says:
This document specifies the Internet Message Format (IMF),
a syntax for *text* messages that are sent between computer
users, within the framework of "electronic mail" messages.
This document specifies a syntax only for *text* messages. In
particular, it makes no provision for the transmission of images,
audio, or other sorts of structured data in electronic mail messages.
A message that is conformant with this specification is composed of
characters with values in the range of 1 through 127 and interpreted
as US-ASCII [ANSI.X3-4.1986] characters.
So, according to this RFC "U+0017 END OF TRANSMISSION BLOCK" does belong in text (as do all the other 27 US-ASCII characters that XML does not support).
/Roger
[1] http://tools.ietf.org/html/rfc5322
