Matching non-whitespace characters in Perl 6

Question

In Perl 6, you can use <.ws> to match non-whitespace characters. I want to match any character that doesn't match <.ws>, but I don't think I can use \S instead because I believe that only matches ASCII spaces while <.ws> will match any Unicode space. How do I do this?

Answer 1

A usage of <.ws> is a call to the ws token that does not capture its result. Its default behavior is:

token ws { <!ww> \s* }

Which means that:

1. We must not be between two word (\w) characters
2. Assuming that is true, there are zero or more whitespace characters at this point

In a given grammar, that can be overridden to specify the "whitespace" of the current language. In the Perl 6 language grammar, for example, ws includes parsing of comments, Pod, and even heredocs!

By contrast, \s is the character class for matching a single whitespace character, and \S means "not a whitespace character". This definition is Unicode based; if we do:

say .uniname for (0..0x10FFFF).map(*.chr).grep(/\s/)

Then we get:

<control-0009>
<control-000A>
<control-000B>
<control-000C>
<control-000D>
SPACE
<control-0085>
NO-BREAK SPACE
OGHAM SPACE MARK
EN SPACE
EM SPACE
EN SPACE
EM SPACE
THREE-PER-EM SPACE
FOUR-PER-EM SPACE
SIX-PER-EM SPACE
FIGURE SPACE
PUNCTUATION SPACE
THIN SPACE
HAIR SPACE
LINE SEPARATOR
PARAGRAPH SEPARATOR
NARROW NO-BREAK SPACE
MEDIUM MATHEMATICAL SPACE
IDEOGRAPHIC SPACE

Therefore, most probably \S is that you are looking for.