Add Object#with_options for DRYing up multiple calls to methods having shared options

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@3314 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

activesupport/CHANGELOG

@@ -1,5 +1,16 @@
 *SVN*
 
+* Add Object#with_options for DRYing up multiple calls to methods having shared options. [Sam Stephenson]  Example:
+
+  ActionController::Routing::Routes.draw do |map|
+    # Account routes
+    map.with_options(:controller => 'account') do |account|
+      account.home   '',       :action => 'dashboard'
+      account.signup 'signup', :action => 'new'
+      account.logout 'logout', :action => 'logout'
+    end
+  end
+
 * Introduce Dependencies.warnings_on_first_load setting.  If true, enables warnings on first load of a require_dependency.  Otherwise, loads without warnings.  Disabled (set to false) by default.  [Jeremy Kemper]
 
 * Active Support is warnings-safe.  #1792 [Eric Hodel]

activesupport/lib/active_support.rb

@@ -32,5 +32,6 @@ require 'active_support/clean_logger'
 require 'active_support/dependencies'
 
 require 'active_support/ordered_options'
+require 'active_support/option_merger'
 
 require 'active_support/values/time_zone'

activesupport/lib/active_support/core_ext/object_and_class.rb

@@ -50,6 +50,10 @@ class Object #:nodoc:
       raise unless exception_classes.any? {|cls| e.kind_of? cls}
     end
   end
+  
+  def with_options(options)
+    yield ActiveSupport::OptionMerger.new(self, options)
+  end
 end
 
 class Class #:nodoc:

activesupport/lib/active_support/option_merger.rb

@@ -0,0 +1,25 @@
+module ActiveSupport
+  class OptionMerger #:nodoc:
+    instance_methods.each do |method| 
+      undef_method(method) if method !~ /^(__|instance_eval)/
+    end
+    
+    def initialize(context, options)
+      @context, @options = context, options
+    end
+    
+    private
+      def method_missing(method, *arguments, &block)
+        merge_argument_options! arguments
+        @context.send(method, *arguments, &block)
+      end
+      
+      def merge_argument_options!(arguments)
+        arguments << if arguments.last.respond_to? :merge!
+          arguments.pop.dup.merge!(@options)
+        else
+          @options.dup
+        end  
+      end
+  end
+end

activesupport/test/option_merger_test.rb

@@ -0,0 +1,32 @@
+require 'test/unit'
+
+$LOAD_PATH.unshift File.dirname(__FILE__) + '/../lib'
+require 'active_support'
+
+class OptionMergerTest < Test::Unit::TestCase
+  def setup
+    @options = {:hello => 'world'}
+  end
+  
+  def test_method_with_options_merges_options_when_options_are_present
+    local_options = {:cool => true}
+    
+    with_options(@options) do |o|
+      assert_equal local_options, method_with_options(local_options)
+      assert_equal @options.merge(local_options), 
+        o.method_with_options(local_options)
+    end
+  end
+  
+  def test_method_with_options_appends_options_when_options_are_missing
+    with_options(@options) do |o|
+      assert_equal Hash.new, method_with_options
+      assert_equal @options, o.method_with_options
+    end
+  end
+
+  private
+    def method_with_options(options = {})
+      options
+    end
+end