Force wrappers name as symbols.

lib/simple_form.rb

@@ -117,7 +117,7 @@ module SimpleForm
 
   # Retrieves a given wrapper
   def self.wrapper(name)
-    if wrapper = @@wrappers[name]
+    if wrapper = @@wrappers[name.to_sym]
       wrapper
     else
       raise WrapperNotFound, "Couldn't find wrapper with name #{name}"
@@ -132,9 +132,9 @@ module SimpleForm
   # and store it in the given name.
   def self.wrappers(*args, &block)
     if block_given?
-      options          = args.extract_options!
-      name             = args.first || :default
-      @@wrappers[name] = build(options, &block)
+      options                 = args.extract_options!
+      name                    = args.first || :default
+      @@wrappers[name.to_sym] = build(options, &block)
     else
       @@wrappers
     end

test/form_builder/wrapper_test.rb

@@ -113,6 +113,15 @@ class WrapperTest < ActionView::TestCase
     assert_select "section.custom_wrapper div.another_wrapper input.string"
   end
 
+  test 'access wrappers with indifferent access' do
+    swap_wrapper :another do
+      with_form_for @user, :name, :wrapper => "another"
+      assert_select "section.custom_wrapper div.another_wrapper label"
+      assert_select "section.custom_wrapper div.another_wrapper input.string"
+      output_buffer.replace ""
+    end
+  end
+
   test 'raise error when wrapper not found' do
     assert_raise SimpleForm::WrapperNotFound do
       with_form_for @user, :name, :wrapper => :not_found