move Dwarn_only and DwarnS_only into @EXPORT and add to Changes

[p5sagit/Data-Dumper-Concise.git] / lib / Data / Dumper / Concise / Sugar.pm

diff --git a/lib/Data/Dumper/Concise/Sugar.pm b/lib/Data/Dumper/Concise/Sugar.pm
index ba85d97..cae80af 100644 (file)
--- a/lib/Data/Dumper/Concise/Sugar.pm
+++ b/lib/Data/Dumper/Concise/Sugar.pm
@@ -7,12 +7,25 @@ use Data::Dumper::Concise ();
 
 BEGIN { @ISA = qw(Exporter) }
 
-@EXPORT = qw(Dwarn DwarnS);
+@EXPORT = qw(Dwarn DwarnS Dwarn_only DwarnS_only);
+
 
 sub Dwarn { warn Data::Dumper::Concise::Dumper @_; @_ }
 
 sub DwarnS ($) { warn Data::Dumper::Concise::Dumper $_[0]; $_[0] }
 
+sub Dwarn_only (&@) {
+  my $only = shift;
+  warn Data::Dumper::Concise::Dumper $only->(@_);
+  @_
+}
+
+sub DwarnS_only (&$) {
+  my $only = shift;
+  warn Data::Dumper::Concise::Dumper do { local $_ = $_[0]; $only->($_[0]) };
+  $_[0]
+}
+
 =head1 NAME
 
 Data::Dumper::Concise::Sugar - return Dwarn @return_value
@@ -45,6 +58,17 @@ is equivalent to:
   warn Dumper($return);
   return $return;
 
+Another trick that is extremely useful when doing method chaining is the
+following:
+
+  my $foo = Bar->new;
+  $foo->bar->baz->Data::Dumper::Concise::Sugar::DwarnS->biff;
+
+which is the same as:
+
+  my $foo = Bar->new;
+  (DwarnS $foo->bar->baz)->biff;
+
 =head1 DESCRIPTION
 
   use Data::Dumper::Concise::Sugar;