module Parameters
  module Types
    class Type

      #
      # The Ruby Class the type represents.
      #
      # @return [Class]
      #   A Ruby Class the Type represents.
      #
      # @abstract
      #
      def self.to_ruby
      end

      #
      # @see to_ruby
      #
      def to_ruby
        self.class.to_ruby
      end

      #
      # Determines if the value is an instance of the Type.
      #
      # @return [Boolean]
      #   Specifies whether the value is already an instance of the Type.
      #
      # @abstract
      #
      def self.===(value)
        false
      end

      #
      # Coerces an Object into an instances of the Type.
      #
      # @param [Object] value
      #   The value to coerce.
      #
      # @return [Object]
      #   The coerced value.
      #
      # @abstract
      #
      def self.coerce(value)
      end

      #
      # Compares the instance type to another instance type.
      #
      # @param [Type] other
      #   The other instance type.
      #
      # @return [::Boolean]
      #   Specifies that the type has the same class as the other instance
      #   type.
      #
      # @since 0.4.0
      #
      def ==(other)
        self.class == other.class
      end

      #
      # Determines if the instance of the type is related to another Type.
      #
      # @param [Type] type
      #   The other type class.
      #
      # @return [::Boolean]
      #   Specifies whether the instance of the type inherites from another
      #   type.
      #
      # @since 0.4.0
      #
      def <(other)
        if other.kind_of?(Type)
          self.class <= other.class
        else
          self.class <= other
        end
      end

      #
      # Compares the type to another instance or class type.
      #
      # @param [Type] type
      #   The other instance or class type.
      #
      # @return [::Boolean]
      #   Specifies whether the instance type inherits from the other
      #   class type, or shares the same class as the other instance type.
      #
      # @since 0.4.0
      #
      def <=(other)
        (self < other) || (self == other)
      end

      #
      # @see ===
      #
      def ===(value)
        self.class === value
      end

      #
      # @see coerce
      #
      def coerce(value)
        self.class.coerce(value)
      end

    end
  end
end