validation-example.rb

class Post < Ohm::Model
  include Ohm::Typecast

  attribute :price, Decimal
end

post = Post.new(:price => "FooBar")
post.price == "FooBar"
# => true

post.valid?
# raises Ohm::Typecast::MissingValidation, with message to add an assert_type_decimal :price"


class Post
  def validate
    assert_type_decimal :price
  end
end

post = Post.new(:price => "FooBar")
post.valid?
post.errors == [[:price, :not_decimal]]
# => true