[XeTeX] Whitespace in input

[Philip TAYLOR]

Ross Moore wrote:
>
> On 16/11/2011, at 5:56 AM, Herbert Schulz wrote:
>
>> Given that TeX (and XeTeX too) deal wit a non-breakble space already (where we usually use the ~ to represent that space) it seems to me that XeTeX should treat that the same way.
>
> No, I disagree completely.
>
> What if you really want the Ux00A0 character to be in the PDF?
> That is, when you copy/paste from the PDF, you want that character
> to come along for the ride.

I'm not sure I entirely go along with this argument, Ross.
"What if you really want the \ character to be in the PDF",
or the "^" character, or the "$" character, or any character
that TeX currently treats specially ?  Whilst I can agree
that there is considerable merit in extending XeTeX such
that it treats all of these "new", "special" characters
specially (by creating new catcodes, new node types and so
on), in the short term I can see no fundamental problem with
treating U+00A0 in such a way that it behaves indistinguishably
from the normal expansion of "~".
>
> In TeX ~ *simulates* a non-breaking space visually, but there is
> no actual character inserted.

And I don't agree that a space is a character, non-breaking or not !

** Phil.