Adding Hash#without Closes #7369 [eventualbuddha]

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@9209 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

activesupport/CHANGELOG

@@ -1,5 +1,7 @@
 *SVN*
 
+* Adding Hash#without Closes #7369 [eventualbuddha]
+
 * TimeWithZone#method_missing: send to utc to advance with dst correctness, otherwise send to time. Adding tests for time calculations methods [Geoff Buesing]
 
 * Add config.active_support.use_standard_json_time_format setting so that Times and Dates export to ISO 8601 dates.  [rick]

activesupport/lib/active_support/core_ext/hash/slice.rb

@@ -11,6 +11,11 @@ module ActiveSupport #:nodoc:
       #   end
       #
       #   search(options.slice(:mass, :velocity, :time))
+      #
+      # Also allows leaving out certain keys. This is useful when duplicating
+      # a hash but omitting a certain subset:
+      #
+      #   Event.new(event.attributes.without(:id, :user_id))
       module Slice
         # Returns a new hash with only the given keys.
         def slice(*keys)
@@ -22,6 +27,17 @@ module ActiveSupport #:nodoc:
         def slice!(*keys)
           replace(slice(*keys))
         end
+
+        # Returns a new hash without the given keys.
+        def without(*keys)
+          allowed = self.keys - (respond_to?(:convert_key) ? keys.map { |key| convert_key(key) } : keys)
+          slice(*allowed)
+        end
+
+        # Replaces the hash without the given keys.
+        def without!(*keys)
+          replace(without(*keys))
+        end
       end
     end
   end

activesupport/test/core_ext/hash_ext_test.rb

@@ -310,6 +310,38 @@ class HashExtTest < Test::Unit::TestCase
     assert_equal expected, original.except!(:c)
     assert_equal expected, original
   end
+
+  def test_without
+    original = { :a => 'x', :b => 'y', :c => 10 }
+    expected = { :a => 'x' }
+
+    # Should return a hash without the given keys.
+    assert_equal expected, original.without(:b, :c)
+    assert_not_equal expected, original
+
+    # Should ignore non-existant keys.
+    assert_equal expected, original.without(:b, :c, :d)
+
+    # Should replace the hash with the given keys taken away.
+    assert_equal expected, original.without!(:b, :c)
+    assert_equal expected, original
+  end
+
+  def test_indifferent_without
+    original = { :a => 'x', :b => 'y', :c => 10 }.with_indifferent_access
+    expected = { :c => 10 }.with_indifferent_access
+
+    [['a', 'b'], [:a, :b]].each do |keys|
+      # Should return a new hash without the given keys.
+      assert_equal expected, original.without(*keys), keys.inspect
+      assert_not_equal expected, original
+
+      # Should replace the hash without the given keys.
+      copy = original.dup
+      assert_equal expected, copy.without!(*keys)
+      assert_equal expected, copy
+    end
+  end
 end
 
 class IWriteMyOwnXML