=item Possessive Quantifiers
-Perl now supports the "possessive quantifier" syntax of the "atomic match"
+Perl now supports the "possessive quantifier" syntax of the "atomic match"
pattern. Basically a possessive quantifier matches as much as it can and never
-gives any back. Thus it can be used to control backtracking. The syntax is
+gives any back. Thus it can be used to control backtracking. The syntax is
similar to non-greedy matching, except instead of using a '?' as the modifier
the '+' is used. Thus C<?+>, C<*+>, C<++>, C<{min,max}+> are now legal
quantifiers. (Yves Orton)
=back
+=item Regexp::Keep internalized
+
+The functionality of Jeff Pinyan's module Regexp::Keep has been added to
+the core. You can now use in regular expressions the special escape C<\K>
+as a way to do something like floating length positive lookbehind. It is
+also useful in substitutions like:
+
+ s/(foo)bar/$1/g
+
+that can now be converted to
+
+ s/foo\Kbar//g
+
+which is much more efficient.
+
=head2 The C<_> prototype
A new prototype character has been added. C<_> is equivalent to C<$> (it