Contents

# encoding: utf-8
# frozen_string_literal: true

module Mixture
  module Types
    # An object.  This adds the basic constraints all types (that
    # inherit from Object) have; i.e., it must be an object, and
    # it must be the type's primitive.
    class Object < Type
      register
      options[:primitive] = ::Object
      options[:method] = :to_object
      as :object

      # This, like {Type.inheritable}, provides a list of inheritable
      # coercions; however, by default, if the requesting type isn't
      # an Object, it _also_ leaves out the Object type; this is so
      # that types that are incompatible with another type all the way
      # up to the Object don't end up getting coerced incorrectly.
      #
      # @return [Array<Class>]
      def self.inheritable
        if self == Object
          super
        else
          ancestors - Object.ancestors
        end
      end

      constraint do |value|
        # This may seem a bit odd, but this returns false for
        # BasicObject; and since this is meant to represent Objects,
        # we want to make sure that the value isn't a BasicObject.
        # rubocop:disable Style/CaseEquality
        ::Object === value
        # rubocop:enable Style/CaseEquality
      end

      # We can't match anything as an object that isn't an object.
      constraint do |value|
        # The first constraint is that the class cannot be an object.
        # This is the same as removing this constraint on inherited
        # classes.
        # The second constraint is that if the class is an object,
        # then the value's class must be object.
        # This is so we can properly infer objects, since it's likely
        # _someone_'s gonna throw us an object.
        self != Object ||
          (self == Object && value.class == ::Object)
      end

      constraint { |value| value.is_a?(options[:primitive]) }
    end
  end
end

Version data entries

2 entries across 2 versions & 1 rubygems

Version	Path
mixture-0.7.1	lib/mixture/types/object.rb
mixture-0.7.0	lib/mixture/types/object.rb