From 87e3b08b45bf7da28cf3b3a80a88d151f479681d Mon Sep 17 00:00:00 2001
From: Ryan Bates <ryan@railscasts.com>
Date: Sat, 7 Jun 2008 14:44:54 -0700
Subject: [PATCH] named_scope with bang

---
 activerecord/lib/active_record/named_scope.rb |   27 ++++++++++++++++++++++--
 activerecord/test/cases/named_scope_test.rb   |    8 +++++++
 2 files changed, 32 insertions(+), 3 deletions(-)

diff --git a/activerecord/lib/active_record/named_scope.rb b/activerecord/lib/active_record/named_scope.rb
index b0c8a8b..131b3dc 100644
--- a/activerecord/lib/active_record/named_scope.rb
+++ b/activerecord/lib/active_record/named_scope.rb
@@ -81,6 +81,15 @@ module ActiveRecord
       #
       #   expected_options = { :conditions => { :colored => 'red' } }
       #   assert_equal expected_options, Shirt.colored('red').proxy_options
+      #
+      #
+      # The bang (!) can be used on a named scope to change the scope in place instead
+      # of returning a new scope. This is useful for building up scopes conditionally.
+      #
+      #   scope = Shirt.dry_clean_only
+      #   scope.colored!(color) if color
+      #
+      # In this example, <tt>scope</tt> is only colored if color is specified.
       def named_scope(name, options = {}, &block)
         scopes[name] = lambda do |parent_scope, *args|
           Scope.new(parent_scope, case options
@@ -102,7 +111,7 @@ module ActiveRecord
       attr_reader :proxy_scope, :proxy_options
 
       [].methods.each do |m|
-        unless m =~ /(^__|^nil\?|^send|^object_id$|class|extend|find|count|sum|average|maximum|minimum|paginate|first|last|empty?)/
+        unless m =~ /(^__|^nil\?|^send|^object_id$|^dup$|class|extend|find|count|sum|average|maximum|minimum|paginate|first|last|empty?)/
           delegate m, :to => :proxy_found
         end
       end
@@ -146,14 +155,26 @@ module ActiveRecord
 
       private
       def method_missing(method, *args, &block)
-        if scopes.include?(method)
-          scopes[method].call(self, *args)
+        m = method.to_s.sub(/!$/, '').to_sym
+        if scopes.include?(m)
+          if method.to_s.ends_with? '!'
+            replace(scopes[m].call(self.dup, *args))
+          else
+            scopes[m].call(self, *args)
+          end
         else
           with_scope :find => proxy_options do
             proxy_scope.send(method, *args, &block)
           end
         end
       end
+      
+      def replace(scope)
+        @proxy_scope = scope.proxy_scope
+        @proxy_options = scope.proxy_options
+        @found = nil
+        self
+      end
 
       def load_found
         @found = find(:all)
diff --git a/activerecord/test/cases/named_scope_test.rb b/activerecord/test/cases/named_scope_test.rb
index d890cf7..eabe090 100644
--- a/activerecord/test/cases/named_scope_test.rb
+++ b/activerecord/test/cases/named_scope_test.rb
@@ -154,4 +154,12 @@ class NamedScopeTest < ActiveRecord::TestCase
       topics.empty?  # use loaded (no query)
     end
   end
+  
+  def test_with_bang
+    scope = Topic.base
+    scope.replied!
+    scope.collect # force load shouldn't effect it
+    scope.approved!
+    assert_equal Topic.base.replied.approved, scope
+  end
 end
-- 
1.5.4.5