::first-word pseudo-element

Hi!

As suggested by Daniel Glazman, I share here my thoughts about the
::first-word selector.

Daniel rightly said that it’s not really possible to determine what a
“Word” is, according to the language.

But the ::first-letter already do this, defining a "letter", wich is
not very clear too. To clarify this, the CSS3 Selectors spec refers to
the Unicode Standard Annex #29 [1].
This document seems very complex to me, but it also contains a “Word
Boundaries” section, which seems to defines exactly that.

So my questions are:
This section could it not be used to clarify what a “word” is?
Otherwise, can’t a selector similar to “::first-chars-before-space” be
used instead?

I’m sorry for my bad english!

Regards,
Pierre Bertet

[1]
http://www.unicode.org/reports/tr29/tr29-9.html