add config for wrapper mappings.

This should be a hash containing an input type as key and the wrapper
that will be used for all inputs with specified type

config.wrapper_mapings = { :string => :string_wrapper }

lib/generators/simple_form/templates/config/initializers/simple_form.rb

@@ -118,6 +118,10 @@
   # matches the regexp as value.
   # config.input_mappings = { /count/ => :integer }
 
+  # Custom wrappers for input types. This should be a hash containing an input
+  # type as key and the wrapper that will be used for all inputs with specified type.
+  # config.wrapper_mappings = { :string => :prepend }
+
   # Default priority for time_zone inputs.
   # config.time_zone_priority = nil
 

lib/simple_form.rb

@@ -95,6 +95,12 @@ module SimpleForm
   mattr_accessor :input_mappings
   @@input_mappings = nil
 
+  # Custom wrappers for input types. This should be a hash containing an input
+  # type as key and the wrapper that will be used for all inputs with specified type
+  # e.g { :string => :string_wrapper, :boolean => :boolean_wrapper }
+  mattr_accessor :wrapper_mappings
+  @@wrapper_mappings = nil
+
   # Default priority for time_zone inputs.
   mattr_accessor :time_zone_priority
   @@time_zone_priority = nil

lib/simple_form/form_builder.rb

@@ -104,15 +104,16 @@ def initialize(*) #:nodoc:
     #
     def input(attribute_name, options={}, &block)
       options = @defaults.deep_dup.deep_merge(options) if @defaults
+      input = find_input(attribute_name, options, &block)
 
       chosen =
-        if name = options[:wrapper]
+        if name = options[:wrapper] || find_wrapper_mapping(input.input_type)
           name.respond_to?(:render) ? name : SimpleForm.wrapper(name)
         else
           wrapper
         end
 
-      chosen.render find_input(attribute_name, options, &block)
+      chosen.render input
     end
     alias :attribute :input
 
@@ -444,6 +445,10 @@ def find_mapping(input_type) #:nodoc:
         end
     end
 
+    def find_wrapper_mapping(input_type)
+      SimpleForm.wrapper_mappings && SimpleForm.wrapper_mappings[input_type]
+    end
+
     # If cache_discovery is enabled, use the class level cache that persists
     # between requests, otherwise use the instance one.
     def discovery_cache #:nodoc:

test/form_builder/wrapper_test.rb

@@ -168,4 +168,14 @@ class WrapperTest < ActionView::TestCase
       with_form_for @user, :name, :wrapper => :not_found
     end
   end
+
+  test 'use wrapper for specified in config mapping' do
+    swap_wrapper :another do
+      swap SimpleForm, :wrapper_mappings => { :string => :another } do
+        with_form_for @user, :name
+        assert_select "section.custom_wrapper div.another_wrapper label"
+        assert_select "section.custom_wrapper div.another_wrapper input.string"
+      end
+    end
+  end
 end