Added Array#to_s(:db) that'll produce a comma-separated list of ids [DHH] Split Grouping into its own file

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@4387 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

5 files changed, 84 insertions, 40 deletions

diff --git a/activesupport/CHANGELOG b/activesupport/CHANGELOG
index 7b98b2dbed..47d1c3ba46 100644
--- a/activesupport/CHANGELOG
+++ b/activesupport/CHANGELOG
@@ -1,5 +1,9 @@
 *SVN*
 
+* Added Array#to_s(:db) that'll produce a comma-separated list of ids [DHH]. Example:
+    
+    Purchase.find(:all, :conditions => [ "product_id IN (?)", shop.products.to_s(:db) ])
+
 * Normalize classify's argument to a String so that it plays nice with Symbols. [Marcel Molina Jr.] 
 
 * Strip out leading schema name in classify. References #5139. [schoenm@earthlink.net]
diff --git a/activesupport/lib/active_support/core_ext/array.rb b/activesupport/lib/active_support/core_ext/array.rb
index 243aeab423..d47b988255 100644
--- a/activesupport/lib/active_support/core_ext/array.rb
+++ b/activesupport/lib/active_support/core_ext/array.rb
@@ -1,44 +1,7 @@
 require File.dirname(__FILE__) + '/array/conversions'
+require File.dirname(__FILE__) + '/array/grouping'
 
 class Array #:nodoc:
   include ActiveSupport::CoreExtensions::Array::Conversions
-
-  # Iterate over an array in groups of a certain size, padding any remaining 
-  # slots with specified value (<tt>nil</tt> by default).
-  # 
-  # E.g.
-  # 
-  #   %w(1 2 3 4 5 6 7).in_groups_of(3) {|g| p g}
-  #   ["1", "2", "3"]
-  #   ["4", "5", "6"]
-  #   ["7", nil, nil]
-  def in_groups_of(number, fill_with = nil, &block)
-    require 'enumerator'
-    collection = dup
-    collection << fill_with until collection.size.modulo(number).zero?
-    grouped_collection = [] unless block_given?
-    collection.each_slice(number) do |group|
-      block_given? ? yield(group) : grouped_collection << group
-    end
-    grouped_collection unless block_given?
-  end
-  
-  # Divide the array into one or more subarrays based on a delimiting +value+
-  # or the result of an optional block.
-  #
-  # ex.
-  #
-  #   [1, 2, 3, 4, 5].split(3)                # => [[1, 2], [4, 5]]
-  #   (1..10).to_a.split { |i| i % 3 == 0 }   # => [[1, 2], [4, 5], [7, 8], [10]]
-  def split(value = nil, &block)
-    block ||= Proc.new { |e| e == value }
-    inject([[]]) do |results, element|
-      if block.call(element)
-        results << []
-      else
-        results.last << element
-      end
-      results
-    end
-  end
+  include ActiveSupport::CoreExtensions::Array::Grouping
 end
diff --git a/activesupport/lib/active_support/core_ext/array/conversions.rb b/activesupport/lib/active_support/core_ext/array/conversions.rb
index b516f58bff..35d010b164 100644
--- a/activesupport/lib/active_support/core_ext/array/conversions.rb
+++ b/activesupport/lib/active_support/core_ext/array/conversions.rb
@@ -26,6 +26,24 @@ module ActiveSupport #:nodoc:
           join '/'
         end
         
+        def self.included(klass) #:nodoc:
+          klass.send(:alias_method, :to_default_s, :to_s)
+          klass.send(:alias_method, :to_s, :to_formatted_s)
+        end
+        
+        def to_formatted_s(format = :default)
+          case format
+            when :db
+              if respond_to?(:empty?) && self.empty?
+                "null"
+              else
+                collect { |element| element.id }.join(",")
+              end
+            else
+              to_default_s
+          end
+        end
+        
         def to_xml(options = {})
           raise "Not all elements respond to to_xml" unless all? { |e| e.respond_to? :to_xml }
 
diff --git a/activesupport/lib/active_support/core_ext/array/grouping.rb b/activesupport/lib/active_support/core_ext/array/grouping.rb
new file mode 100644
index 0000000000..6f28e1eb6d
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/array/grouping.rb
@@ -0,0 +1,46 @@
+module ActiveSupport #:nodoc:
+  module CoreExtensions #:nodoc:
+    module Array #:nodoc:
+      module Grouping
+        # Iterate over an array in groups of a certain size, padding any remaining 
+        # slots with specified value (<tt>nil</tt> by default).
+        # 
+        # E.g.
+        # 
+        #   %w(1 2 3 4 5 6 7).in_groups_of(3) {|g| p g}
+        #   ["1", "2", "3"]
+        #   ["4", "5", "6"]
+        #   ["7", nil, nil]
+        def in_groups_of(number, fill_with = nil, &block)
+          require 'enumerator'
+          collection = dup
+          collection << fill_with until collection.size.modulo(number).zero?
+          grouped_collection = [] unless block_given?
+          collection.each_slice(number) do |group|
+            block_given? ? yield(group) : grouped_collection << group
+          end
+          grouped_collection unless block_given?
+        end
+
+        # Divide the array into one or more subarrays based on a delimiting +value+
+        # or the result of an optional block.
+        #
+        # ex.
+        #
+        #   [1, 2, 3, 4, 5].split(3)                # => [[1, 2], [4, 5]]
+        #   (1..10).to_a.split { |i| i % 3 == 0 }   # => [[1, 2], [4, 5], [7, 8], [10]]
+        def split(value = nil, &block)
+          block ||= Proc.new { |e| e == value }
+          inject([[]]) do |results, element|
+            if block.call(element)
+              results << []
+            else
+              results.last << element
+            end
+            results
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/activesupport/test/core_ext/array_ext_test.rb b/activesupport/test/core_ext/array_ext_test.rb
index 0d5f58a9be..4cef0120d6 100644
--- a/activesupport/test/core_ext/array_ext_test.rb
+++ b/activesupport/test/core_ext/array_ext_test.rb
@@ -13,7 +13,7 @@ class ArrayExtToParamTests < Test::Unit::TestCase
   end
 end
 
-class ArrayExtConversionTests < Test::Unit::TestCase
+class ArrayExtToSentenceTests < Test::Unit::TestCase
   def test_plain_array_to_sentence
     assert_equal "", [].to_sentence
     assert_equal "one", ['one'].to_sentence
@@ -39,6 +39,19 @@ class ArrayExtConversionTests < Test::Unit::TestCase
   end
 end
 
+class ArrayExtToSTests < Test::Unit::TestCase
+  def test_to_s_db
+    collection = [
+      Class.new { def id() 1 end }.new,
+      Class.new { def id() 2 end }.new,
+      Class.new { def id() 3 end }.new
+    ]
+    
+    assert_equal "null", [].to_s(:db)
+    assert_equal "1,2,3", collection.to_s(:db)
+  end
+end
+
 class ArrayExtGroupingTests < Test::Unit::TestCase
   def test_group_by_with_perfect_fit
     groups = []