RE: [xml-dev] US-ASCII characters versus XML characters ... whysuch a h

["Costello, Roger L." <costello@mitre.org>]

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