Allow validates to map some types to specific options. So now you can do:

validates :email, :presence => true, :format => /@/
  validates :genre, :inclusion => %w(m f)
  validates :password, :length => 6..20

activemodel/lib/active_model/validations/numericality.rb

@@ -10,9 +10,10 @@ module ActiveModel
       end
 
       def check_validity!
-        options.slice(*CHECKS.keys) do |option, value|
-          next if [:odd, :even].include?(option)
-          raise ArgumentError, ":#{option} must be a number, a symbol or a proc" unless value.is_a?(Numeric) || value.is_a?(Proc) || value.is_a?(Symbol)
+        keys = CHECKS.keys - [:odd, :event]
+        options.slice(*keys) do |option, value|
+          next if value.is_a?(Numeric) || value.is_a?(Proc) || value.is_a?(Symbol)
+          raise ArgumentError, ":#{option} must be a number, a symbol or a proc"
         end
       end
 

activemodel/lib/active_model/validations/validates.rb

@@ -7,6 +7,7 @@ module ActiveModel
       # custom validator classes in their place such as PresenceValidator.
       # 
       # Examples of using the default rails validators:
+      #
       #   validates :terms, :acceptance => true
       #   validates :password, :confirmation => true
       #   validates :username, :exclusion => { :in => %w(admin superuser) }
@@ -19,6 +20,7 @@ module ActiveModel
       # 
       # The power of the +validates+ method comes when using cusom validators
       # and default validators in one call for a given attribute e.g.
+      #
       #   class EmailValidator < ActiveModel::EachValidator
       #     def validate_each(record, attribute, value)
       #       record.errors[attribute] << (options[:message] || "is not an email") unless
@@ -31,29 +33,32 @@ module ActiveModel
       #     attr_accessor :name, :email
       # 
       #     validates :name, :presence => true, :uniqueness => true, :length => { :maximum => 100 }
-      #     validates :email, :presence => true, :format => { :with => /@/ }
+      #     validates :email, :presence => true, :email => true
       #   end
       # 
       # Validator classes my also exist within the class being validated
       # allowing custom modules of validators to be included as needed e.g.
-      # 
-      #   module MyValidators
+      #
+      #   class Film
+      #     include ActiveModel::Validations
+      #
       #     class TitleValidator < ActiveModel::EachValidator
       #       def validate_each(record, attribute, value)
       #         record.errors[attribute] << "must start with 'the'" unless =~ /^the/i
       #       end
       #     end
+      #
+      #     validates :name, :title => true
       #   end
       #
-      #   class Film
-      #     include ActiveModel::Validations
-      #     include MyValidators
-      # 
-      #     validates :name, :title => true
-      #   end 
+      # The validators hash can also handle regular expressions, ranges and arrays:
       #
-      # The options :if, :unless, :on, :allow_blank and :allow_nil can be given to one specific
-      # validator:
+      #   validates :email, :format => /@/
+      #   validates :genre, :inclusion => %w(mail female)
+      #   validates :password, :length => 6..20
+      #
+      # Finally, the options :if, :unless, :on, :allow_blank and :allow_nil can be given
+      # to one specific validator:
       #
       #   validates :password, :presence => { :if => :password_required? }, :confirmation => true
       #
@@ -78,7 +83,22 @@ module ActiveModel
             raise ArgumentError, "Unknown validator: '#{key}'"
           end
 
-          validates_with(validator, defaults.merge(options == true ? {} : options))
+          validates_with(validator, defaults.merge(_parse_validates_options(options)))
+        end
+      end
+
+    protected
+
+      def _parse_validates_options(options) #:nodoc:
+        case options
+        when TrueClass
+          {}
+        when Hash
+          options
+        when Regexp
+          { :with => options }
+        when Range, Array
+          { :in => options }
         end
       end
     end

activemodel/test/cases/validations/validates_test.rb

@@ -10,43 +10,42 @@ class ValidatesTest < ActiveModel::TestCase
 
   def reset_callbacks
     Person.reset_callbacks(:validate)
+    PersonWithValidator.reset_callbacks(:validate)
   end
 
   def test_validates_with_built_in_validation
     Person.validates :title, :numericality => true
     person = Person.new
     person.valid?
-    assert person.errors[:title].include?('is not a number')
+    assert_equal ['is not a number'], person.errors[:title]
   end
 
   def test_validates_with_built_in_validation_and_options
-    Person.validates :title, :numericality => { :message => 'my custom message' }
+    Person.validates :salary, :numericality => { :message => 'my custom message' }
     person = Person.new
     person.valid?
-    assert person.errors[:title].include?('my custom message')
+    assert_equal ['my custom message'], person.errors[:salary]
   end
   
   def test_validates_with_validator_class
     Person.validates :karma, :email => true
     person = Person.new
     person.valid?
-    assert person.errors[:karma].include?('is not an email')
+    assert_equal ['is not an email'], person.errors[:karma]
   end
 
   def test_validates_with_if_as_local_conditions
     Person.validates :karma, :presence => true, :email => { :unless => :condition_is_true }
     person = Person.new
     person.valid?
-    assert !person.errors[:karma].include?('is not an email')
-    assert person.errors[:karma].include?('can\'t be blank')
+    assert_equal ["can't be blank"], person.errors[:karma]
   end
 
   def test_validates_with_if_as_shared_conditions
     Person.validates :karma, :presence => true, :email => true, :if => :condition_is_true
     person = Person.new
     person.valid?
-    assert person.errors[:karma].include?('is not an email')
-    assert person.errors[:karma].include?('can\'t be blank')
+    assert ["can't be blank", "is not an email"], person.errors[:karma].sort
   end
 
   def test_validates_with_unless_shared_conditions
@@ -61,11 +60,38 @@ class ValidatesTest < ActiveModel::TestCase
     assert person.valid?
   end
 
+  def test_validates_with_regexp
+    Person.validates :karma, :format => /positive|negative/
+    person = Person.new
+    assert person.invalid?
+    assert_equal ['is invalid'], person.errors[:karma]
+    person.karma = "positive"
+    assert person.valid?
+  end
+
+  def test_validates_with_array
+    Person.validates :genre, :inclusion => %w(m f)
+    person = Person.new
+    assert person.invalid?
+    assert_equal ['is not included in the list'], person.errors[:genre]
+    person.genre = "m"
+    assert person.valid?
+  end
+
+  def test_validates_with_range
+    Person.validates :password, :length => 6..20
+    person = Person.new
+    assert person.invalid?
+    assert_equal ['is too short (minimum is 6 characters)'], person.errors[:password]
+    person.password = '123456'
+    assert person.valid?
+  end
+
   def test_validates_with_validator_class_and_options
     Person.validates :karma, :email => { :message => 'my custom message' }
     person = Person.new
     person.valid?
-    assert person.errors[:karma].include?('my custom message')
+    assert_equal ['my custom message'], person.errors[:karma]
   end
   
   def test_validates_with_unknown_validator
@@ -76,13 +102,13 @@ class ValidatesTest < ActiveModel::TestCase
     PersonWithValidator.validates :title, :presence => true
     person = PersonWithValidator.new
     person.valid?
-    assert person.errors[:title].include?('Local validator')
+    assert_equal ['Local validator'], person.errors[:title]
   end
   
   def test_validates_with_included_validator_and_options
     PersonWithValidator.validates :title, :presence => { :custom => ' please' }
     person = PersonWithValidator.new
     person.valid?
-    assert person.errors[:title].include?('Local validator please')
+    assert_equal ['Local validator please'], person.errors[:title]
   end
 end

activemodel/test/models/person.rb

@@ -2,7 +2,7 @@ class Person
   include ActiveModel::Validations
   extend  ActiveModel::Translation
 
-  attr_accessor :title, :karma, :salary
+  attr_accessor :title, :karma, :salary, :genre, :password
 
   def condition_is_true
     true