remove form_for case statement

actionpack/lib/action_view/helpers.rb

@@ -1,3 +1,5 @@
+require 'action_view/helpers/form_helper_core_extensions'
+
 module ActionView #:nodoc:
   module Helpers #:nodoc:
     autoload :ActiveRecordHelper, 'action_view/helpers/active_record_helper'

actionpack/lib/action_view/helpers/form_helper.rb

@@ -232,30 +232,29 @@ module FormHelper
       def form_for(record_or_name_or_array, *args, &proc)
         raise ArgumentError, "Missing block" unless block_given?
 
+        object, object_name, options = standardize_form_invocation!(record_or_name_or_array, args)
+
+        concat(form_tag(options.delete(:url) || {}, options.delete(:html) || {}))
+        fields_for(object_name, *(args << options), &proc)
+        concat('</form>')
+      end
+
+      def standardize_form_invocation!(record_or_name_or_array, args)
         options = args.extract_options!
 
-        case record_or_name_or_array
-        when String, Symbol
-          object_name = record_or_name_or_array
-        when Array
-          object = record_or_name_or_array.last
-          object_name = ActionController::RecordIdentifier.singular_class_name(object)
-          apply_form_for_options!(record_or_name_or_array, options)
-          args.unshift object
-        else
-          object = record_or_name_or_array
-          object_name = ActionController::RecordIdentifier.singular_class_name(object)
-          apply_form_for_options!([object], options)
+        object      = record_or_name_or_array.as_form_object
+        object_name = object.form_object_name
+
+        if object.acts_like_model?
+          apply_form_for_options!(record_or_name_or_array.as_array, options)
           args.unshift object
         end
-
-        concat(form_tag(options.delete(:url) || {}, options.delete(:html) || {}))
-        fields_for(object_name, *(args << options), &proc)
-        concat('</form>')
+
+        [object, object_name, options]
       end
 
       def apply_form_for_options!(object_or_array, options) #:nodoc:
-        object = object_or_array.is_a?(Array) ? object_or_array.last : object_or_array
+        object = object_or_array.as_form_object
 
         html_options =
           if object.respond_to?(:new_record?) && object.new_record?
@@ -300,14 +299,8 @@ def fields_for(record_or_name_or_array, *args, &block)
         raise ArgumentError, "Missing block" unless block_given?
         options = args.extract_options!
 
-        case record_or_name_or_array
-        when String, Symbol
-          object_name = record_or_name_or_array
-          object = args.first
-        else
-          object = record_or_name_or_array
-          object_name = ActionController::RecordIdentifier.singular_class_name(object)
-        end
+        object      = record_or_name_or_array.as_fields_for_form_object(args)
+        object_name = record_or_name_or_array.form_object_name
 
         builder = options[:builder] || ActionView::Base.default_form_builder
         yield builder.new(object_name, object, self, options, block)

actionpack/lib/action_view/helpers/form_helper_core_extensions.rb

@@ -0,0 +1,59 @@
+class String
+  def form_object_name
+    self
+  end
+
+  def as_fields_for_form_object(args)
+    args.first
+  end
+
+  def acts_like_model?
+    false
+  end
+end
+
+class Symbol
+  def form_object_name
+    self
+  end
+
+  def as_fields_for_form_object(args)
+    args.first
+  end
+
+  def acts_like_model?
+    false
+  end
+end
+
+class Array
+  def as_form_object
+    last
+  end
+
+  def as_array
+    self
+  end
+end
+
+class Object
+  def as_form_object
+    self
+  end
+
+  def as_fields_for_form_object(args)
+    as_form_object
+  end
+
+  def form_object_name
+    ActionController::RecordIdentifier.singular_class_name(self)
+  end
+
+  def as_array
+    [self]
+  end
+
+  def acts_like_model?
+    true
+  end
+end

actionpack/lib/action_view/helpers/prototype_helper.rb

@@ -374,23 +374,8 @@ def form_remote_tag(options = {}, &block)
       #
       # See FormHelper#form_for for additional semantics.
       def remote_form_for(record_or_name_or_array, *args, &proc)
-        options = args.extract_options!
-
-        case record_or_name_or_array
-        when String, Symbol
-          object_name = record_or_name_or_array
-        when Array
-          object = record_or_name_or_array.last
-          object_name = ActionController::RecordIdentifier.singular_class_name(object)
-          apply_form_for_options!(record_or_name_or_array, options)
-          args.unshift object
-        else
-          object      = record_or_name_or_array
-          object_name = ActionController::RecordIdentifier.singular_class_name(record_or_name_or_array)
-          apply_form_for_options!(object, options)
-          args.unshift object
-        end
-
+        object, object_name, options = standardize_form_invocation!(record_or_name_or_array, args)
+
         concat(form_remote_tag(options))
         fields_for(object_name, *(args << options), &proc)
         concat('</form>')