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Diffstat (limited to 'pod/perlre.pod')
| -rw-r--r-- | pod/perlre.pod | 19 |
1 files changed, 17 insertions, 2 deletions
diff --git a/pod/perlre.pod b/pod/perlre.pod index 772a8bc418..b69c359006 100644 --- a/pod/perlre.pod +++ b/pod/perlre.pod @@ -513,8 +513,23 @@ X<metacharacter> X<quantifier> X<*> X<+> X<?> X<{n}> X<{n,}> X<{n,m}> (If a curly bracket occurs in any other context and does not form part of a backslashed sequence like C<\x{...}>, it is treated -as a regular character. In particular, the lower bound -is not optional.) The "*" quantifier is equivalent to C<{0,}>, the "+" +as a regular character. In particular, the lower quantifier bound +is not optional. However, in Perl v5.18, it is planned to issue a +deprecation warning for all such occurrences, and in Perl v5.20 to +require literal uses of a curly bracket to be escaped, say by preceding +them with a backslash or enclosing them within square brackets, (C<"\{"> +or C<"[{]">). This change will allow for future syntax extensions (like +making the lower bound of a quantifier optional), and better error +checking of quantifiers. Now, a typo in a quantifier silently causes +it to be treated as the literal characters. For example, + + /o{4,3}/ + +looks like a quantifier that matches 0 times, since 4 is greater than 3, +but it really means to match the sequence of six characters +S<C<"o { 4 , 3 }">>.) + +The "*" quantifier is equivalent to C<{0,}>, the "+" quantifier to C<{1,}>, and the "?" quantifier to C<{0,1}>. n and m are limited to non-negative integral values less than a preset limit defined when perl is built. This is usually 32766 on the most common platforms. The actual limit can |