[XeTeX] Whitespace in input

[Philip TAYLOR]

mskala at ansuz.sooke.bc.ca wrote:

<various points with which I have no reason to disagree at this time, followed by>

 > 2. Inevitably, people will include invalid characters in TeX input; and
 > U+00A0 is an invalid character for TeX input.

Firstly (as is clear from the list on which we are discussing
this), we are not discussing TeX but XeTeX.  Secondly, even
if we were discussing TeX, on what basis do you claim that
U+00A0 is invalid ?  And if you assert that it is, /a priori/,
invalid for TeX, and if your reasons for that assertion are
sound, do they also support the assertion that it is, /a priori/,
invalid for XeTeX ?

Remainder snipped, so that we can debate one point at a time.

Philip Taylor