that they are only guaranteed to be defined after a
successful match that was executed with the C (preserve) modifier.
The use of these variables incurs no global performance penalty, unlike
-their punctuation char equivalents, however at the trade-off that you
-have to tell perl when you want to use them. As of Perl 5.18, these three
+their punctuation character equivalents, however at the trade-off that you
+have to tell perl when you want to use them. As of Perl 5.20, these three
variables are equivalent to C<$`>, C<$&> and C<$'>, and C is ignored.
X X
@@ -909,7 +1299,8 @@ X
X
Backslashed metacharacters in Perl are alphanumeric, such as C<\b>,
C<\w>, C<\n>. Unlike some other regular expression languages, there
are no backslashed symbols that aren't alphanumeric. So anything
-that looks like \\, \(, \), \[, \], \{, or \} is always
+that looks like C<\\>, C<\(>, C<\)>, C<\[>, C<\]>, C<\{>, or C<\}> is
+always
interpreted as a literal character, not a metacharacter. This was
once used in a common idiom to disable or quote the special meanings
of regular expression metacharacters in a string that you want to
@@ -918,9 +1309,9 @@ use for a pattern. Simply quote all non-"word" characters:
$pattern =~ s/(\W)/\\$1/g;
(If C