=item Comments Inside the Regex
The C</x> modifier causes whitespace to be ignored in a regex pattern
-(except in a character class), and also allows you to use normal
-comments there, too. As you can imagine, whitespace and comments help
-a lot.
+(except in a character class and a few other places), and also allows you to
+use normal comments there, too. As you can imagine, whitespace and comments
+help a lot.
C</x> lets you turn this:
the C<(?...)> construct. See below.
The C</x> modifier itself needs a little more explanation. It tells
-the regular expression parser to ignore whitespace that is neither
+the regular expression parser to ignore most whitespace that is neither
backslashed nor within a character class. You can use this to break up
your regular expression into (slightly) more readable parts. The C<#>
character is also treated as a metacharacter introducing a comment,
just as in ordinary Perl code. This also means that if you want real
whitespace or C<#> characters in the pattern (outside a character
class, where they are unaffected by C</x>), then you'll either have to
-escape them (using backslashes or C<\Q...\E>) or encode them using octal
-or hex escapes. Taken together, these features go a long way towards
+escape them (using backslashes or C<\Q...\E>) or encode them using octal,
+hex, or C<\N{}> escapes. Taken together, these features go a long way towards
making Perl's regular expressions more readable. Note that you have to
be careful not to include the pattern delimiter in the comment--perl has
no way of knowing you did not intend to close the pattern early. See
the C-comment deletion code in L<perlop>. Also note that anything inside
-a C<\Q...\E> stays unaffected by C</x>.
+a C<\Q...\E> stays unaffected by C</x>. Also note that space is never allowed
+within a L<quantifier|Quantifiers> such as C<{3}> or C<{5,}>, regardless of
+C</x>, nor is space allowed before the C<{> or within the braces in C<\x{...}>
+nor C<\N{U+...}>. Similarly space is not allowed before the C<{> in
+C<\N{I<name>}> and is currently significant within the braces.
X</x>
=head2 Regular Expressions