update 'say' docs to better represent reality

[perl5.git] / pod / perl5100delta.pod

diff --git a/pod/perl5100delta.pod b/pod/perl5100delta.pod
index 263f158..6728559 100644 (file)
--- a/pod/perl5100delta.pod
+++ b/pod/perl5100delta.pod
@@ -200,6 +200,23 @@ logically match their complements.
 C<\R> matches a generic linebreak, that is, vertical whitespace, plus
 the multi-character sequence C<"\x0D\x0A">.
 
+=item Optional pre-match and post-match captures with the /p flag
+
+There is a new flag C</p> for regular expressions.  Using this
+makes the engine preserve a copy of the part of the matched string before
+the matching substring to the new special variable C<${^PREMATCH}>, the
+part after the matching substring to C<${^POSTMATCH}>, and the matched
+substring itself to C<${^MATCH}>.
+
+Perl is still able to store these substrings to the special variables
+C<$`>, C<$'>, C<$&>, but using these variables anywhere in the program
+adds a penalty to all regular expression matches, whereas if you use
+the C</p> flag and the new special variables instead, you pay only for
+the regular expressions where the flag is used.
+
+For more detail on the new variables, see L<perlvar>; for the use of
+the regular expression flag, see L<perlop> and L<perlre>.
+
 =back
 
 =head2 C<say()>
@@ -625,6 +642,27 @@ Previously, the exception would not occur until Perl attempted to make
 use of the recursive inheritance while resolving a method or doing a
 C<$foo-E<gt>isa($bar)> lookup.
 
+=head2 warnings::enabled and warnings::warnif changed to favor users of modules
+
+The behaviour in 5.10.x favors the person using the module;
+The behaviour in 5.8.x favors the module writer;
+
+Assume the following code:
+
+  main calls Foo::Bar::baz()
+  Foo::Bar inherits from Foo::Base
+  Foo::Bar::baz() calls Foo::Base::_bazbaz()
+  Foo::Base::_bazbaz() calls: warnings::warnif('substr', 'some warning 
+message');
+
+On 5.8.x, the code warns when Foo::Bar contains C<use warnings;>
+It does not matter if Foo::Base or main have warnings enabled
+to disable the warning one has to modify Foo::Bar.
+
+On 5.10.0 and newer, the code warns when main contains C<use warnings;>
+It does not matter if Foo::Base or Foo::Bar have warnings enabled
+to disable the warning one has to modify main.
+
 =head1 Modules and Pragmata
 
 =head2 Upgrading individual core modules
@@ -823,7 +861,7 @@ of C<CPANPLUS>.
 =item *
 
 C<Archive::Extract> is a generic archive extraction mechanism
-for F<.tar> (plain, gziped or bzipped) or F<.zip> files.
+for F<.tar> (plain, gzipped or bzipped) or F<.zip> files.
 
 =item *
 
@@ -977,7 +1015,7 @@ The L<perlreapi> manpage describes the interface to the perl interpreter
 used to write pluggable regular expression engines (by Ævar Arnfjörð
 Bjarmason).
 
-The L<perlunitut> manpage is an tutorial for programming with Unicode and
+The L<perlunitut> manpage is a tutorial for programming with Unicode and
 string encodings in Perl, courtesy of Juerd Waalboer.
 
 A new manual page, L<perlunifaq> (the Perl Unicode FAQ), has been added
@@ -1538,7 +1576,7 @@ inherits from C<B::SV> (it used to inherit from C<B::IV>).
 
 The anonymous hash and array constructors now take 1 op in the optree
 instead of 3, now that pp_anonhash and pp_anonlist return a reference to
-an hash/array when the op is flagged with OPf_SPECIAL. (Nicholas Clark)
+a hash/array when the op is flagged with OPf_SPECIAL. (Nicholas Clark)
 
 =head1 Known Problems