Christoph February 2016
Tabulators are of category Control, not Space. The property you're interested in is actually called White_Space, and that's what you need to use in Perl 6:
say so "\t" ~~ /<:White_Space>/
Several alternative spellings appear to be available as well, including WhiteSpace, WSpace and its lower-case variants, but not WS.
There is also a built-in rule
<ws>, which matches zero or more whitespace characters instead of a single one, and of course
\s, which already uses Unicode semantics.