Detect label and value automatically.

TODO.rdoc

@@ -5,7 +5,6 @@
 * Sample CSS
 * Test forms with non objects
 * Get default string options from column definition
-* Detect label and values automatically
 * Add support to default :prompt methods on datetime inputs
 * Add support to default label method
 * Add wrapper support

lib/simple_form.rb

@@ -18,4 +18,12 @@ module SimpleForm
     SimpleForm::Components::Label, SimpleForm::Components::Input,
     SimpleForm::Components::Hint,  SimpleForm::Components::Error
   ]
+
+  # Series of attemps to detect a default label method for collection
+  mattr_accessor :collection_label_methods
+  @@collection_label_methods = [ :name, :title, :to_s ]
+
+  # Series of attemps to detect a default value method for collection
+  mattr_accessor :collection_value_methods
+  @@collection_value_methods = [ :id, :to_s ]
 end

lib/simple_form/components/input.rb

@@ -57,19 +57,19 @@ module SimpleForm
       end
 
       def detect_collection_methods(collection, options)
-        case collection.first
+        sample = collection.first || collection.last
+
+        case sample
           when Array
             label, value = :first, :last
           when Integer
-            value = :to_i
-          when String
-            # Do nothing ...
-          else
-            # TODO Implement detection logic
+            label, value = :to_s, :to_i
+          when String, NilClass
+            label, value = :to_s, :to_s
         end
 
-        options[:label_method] ||= label || :to_s
-        options[:value_method] ||= value || :to_s
+        options[:label_method] ||= label || SimpleForm.collection_label_methods.find { |m| sample.respond_to?(m) }
+        options[:value_method] ||= value || SimpleForm.collection_value_methods.find { |m| sample.respond_to?(m) }
       end
     end
   end

test/components/input_test.rb

@@ -190,6 +190,13 @@ class InputTest < ActionView::TestCase
     assert_no_select 'select option[value=]', ""
   end
 
+  test 'input should detect label and value on collections' do
+    users = [ setup_new_user(:id => 1, :name => "Jose"), setup_new_user(:id => 2, :name => "Carlos") ]
+    with_input_for :description, :select, :collection => users
+    assert_select 'select option[value=1]', 'Jose'
+    assert_select 'select option[value=2]', 'Carlos'
+  end
+
   test 'input should allow overriding collection for radio types' do
     with_input_for :name, :radio, :collection => ['Jose', 'Carlos']
     assert_select 'input[type=radio][value=Jose]'

test/support/models.rb

@@ -10,9 +10,11 @@ class Column
 end
 
 class User < OpenStruct
+  attr_reader :id
 
-  def id
-    1
+  def initialize(attributes={})
+    @id = attributes.delete(:id)
+    super
   end
 
   def new_record?

test/test_helper.rb

@@ -32,12 +32,13 @@ class ActionView::TestCase
     @response = MockResponse.new(self)
   end
 
-  def setup_new_user
-    @user = User.new(
+  def setup_new_user(options={})
+    @user = User.new({
+      :id => 1,
       :name => 'New in Simple Form!',
       :description => 'Hello!',
       :created_at => Time.now
-    )
+    }.merge(options))
   end
 
   def protect_against_forgery?