From 51730792ca930a896361eb92354a42bc56903de1 Mon Sep 17 00:00:00 2001
From: Pratik Naik <pratiknaik@gmail.com>
Date: Wed, 19 Nov 2008 19:36:42 +0530
Subject: Added Object#try. ( Taken from http://ozmm.org/posts/try.html )
 [Chris Wanstrath]

---
 activesupport/CHANGELOG                            |  2 ++
 .../lib/active_support/core_ext/object/misc.rb     | 13 +++++++++++
 .../test/core_ext/object_and_class_ext_test.rb     | 25 ++++++++++++++++++++++
 3 files changed, 40 insertions(+)

(limited to 'activesupport')

diff --git a/activesupport/CHANGELOG b/activesupport/CHANGELOG
index 5997b7daaf..0717d344d7 100644
--- a/activesupport/CHANGELOG
+++ b/activesupport/CHANGELOG
@@ -1,5 +1,7 @@
 *2.3.0 [Edge]*
 
+* Added Object#try. ( Taken from http://ozmm.org/posts/try.html ) [Chris Wanstrath]
+
 * Added Enumerable#none? to check that none of the elements match the block #1408 [Damian Janowski]
 
 * TimeZone offset tests: use current_period, to ensure TimeZone#utc_offset is up-to-date [Geoff Buesing]
diff --git a/activesupport/lib/active_support/core_ext/object/misc.rb b/activesupport/lib/active_support/core_ext/object/misc.rb
index cd0a04d32a..50f824c358 100644
--- a/activesupport/lib/active_support/core_ext/object/misc.rb
+++ b/activesupport/lib/active_support/core_ext/object/misc.rb
@@ -71,4 +71,17 @@ class Object
   def acts_like?(duck)
     respond_to? "acts_like_#{duck}?"
   end
+
+  # Tries to send the method only if object responds to it. Return +nil+ otherwise.
+  # 
+  # ==== Example :
+  # 
+  # # Without try
+  # @person ? @person.name : nil
+  # 
+  # With try
+  # @person.try(:name)
+  def try(method)
+    send(method) if respond_to?(method, true)
+  end
 end
diff --git a/activesupport/test/core_ext/object_and_class_ext_test.rb b/activesupport/test/core_ext/object_and_class_ext_test.rb
index e88dcb52d5..fbdce56ac2 100644
--- a/activesupport/test/core_ext/object_and_class_ext_test.rb
+++ b/activesupport/test/core_ext/object_and_class_ext_test.rb
@@ -247,3 +247,28 @@ class ObjectInstanceVariableTest < Test::Unit::TestCase
       [arg] + instance_exec('bar') { |v| [reverse, v] } }
   end
 end
+
+class ObjectTryTest < Test::Unit::TestCase
+  def setup
+    @string = "Hello"
+  end
+
+  def test_nonexisting_method
+    method = :undefined_method
+    assert !@string.respond_to?(method)
+    assert_nil @string.try(method)
+  end
+  
+  def test_valid_method
+    assert_equal 5, @string.try(:size)
+  end
+
+  def test_valid_private_method
+    class << @string
+      private :size
+    end
+
+    assert_equal 5, @string.try(:size)
+  end
+
+end
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