Ticket #7638: composed_of_form_helpers_documentation.diff

activerecord/lib/active_record/aggregations.rb

@@ -108 +108 @@
-    # 
-    # Read more about value objects on http://c2.com/cgi/wiki?ValueObject and on the dangers of not keeping value objects
-    # immutable on http://c2.com/cgi/wiki?ValueObjectsShouldBeImmutable
+    #
+    # == Using value objects with form helpers
+    #
+    # Because the form helpers use value_before_typecast for rendering values, the helpers will always render with the raw value
+    # rather than the content of value object's to_s method, as one might expect. Because of this, a correct value needs to be
+    # supplied to the helper. Example:
+    #
+    #   <%= input(:product, :price, :value => @product.price.to_s) %>
-    module ClassMethods
-      # Adds reader and writer methods for manipulating a value object:
-      # <tt>composed_of :address</tt> adds <tt>address</tt> and <tt>address=(new_address)</tt> methods.