Adding a placeholder option to the string input and have it use

i18n translation, when possible.

lib/simple_form/components/hints.rb

@@ -18,4 +18,4 @@ module SimpleForm
       end
     end
   end
-end
+end

lib/simple_form/inputs/string_input.rb

@@ -7,9 +7,10 @@ module SimpleForm
 
       def input_html_options
         input_options = super
-        input_options[:size]      ||= [limit, SimpleForm.default_input_size].compact.min
-        input_options[:maxlength] ||= limit if limit
-        input_options[:type]      ||= input_type unless input_type == :string
+        input_options[:size]        ||= [limit, SimpleForm.default_input_size].compact.min
+        input_options[:maxlength]   ||= limit if limit
+        input_options[:type]        ||= input_type unless input_type == :string
+        input_options[:placeholder] ||= placeholder if placeholder
         input_options
       end
 
@@ -22,6 +23,10 @@ module SimpleForm
       def limit
         column && column.limit
       end
+
+      def placeholder
+        @placeholder ||= options[:placeholder] || translate(:placeholder)
+      end
     end
   end
 end

test/inputs_test.rb

@@ -48,6 +48,20 @@ class InputTest < ActionView::TestCase
     assert_select 'input.string[size=50]'
   end
 
+  test 'input should accept the placeholder option' do
+    with_input_for @user, :name, :string, :placeholder => 'Put in some text'
+    assert_select 'input.string[placeholder=Put in some text]'
+  end
+
+  test 'input should use i18n to translate placeholder text' do
+    store_translations(:en, :simple_form => { :placeholder => { :user => {
+      :name => 'Name goes here'
+    } } }) do
+      with_input_for @user, :name, :string
+      assert_select 'input.string[placeholder=Name goes here]'
+    end
+  end
+
   # NumericInput
   test 'input should generate an integer text field for integer attributes ' do
     with_input_for @user, :age, :integer