Short scopes and predicates (similar functionality exists in ActiveRecord::Enum).

[MityaLiu]

@albertosaurus
I'm currently using short scopes and predicates defined as ActiveSupport::Concern.
If I make a PR would you be interested in adding such functionality?
I'm asking because it'll take me a day to port this code and add specs.
It allows the following syntax:

has_enumerated :status, short_scopes: true, predicates: true
# existing => new
booking.with_status(:active) => booking.active
booking.all_except(:active) => booking.not_active
booking.status === :rejected => booking.rejected?

# Extensions for PowerEnum
module PowerEnumEnhancements
  extend ActiveSupport::Concern

  # TODO: Consider making a PR to PowerEnum
  module ClassMethods
    # Dynamically defines predicate methods from enum names
    # @param [Symbol] relation_name
    # @return [Nil]
    private def define_enum_predicates(relation_name)
      reflection = find_reflection_by_name!(relation_name)
      if enum_table_exists?(reflection)
        reflection.klass.names.each do |name|
          define_method("#{name}?") do
            public_send(reflection.name).like?(name)
          end
        end
      end
    end

    # Dynamically defines scopes from enum names
    # @param [Symbol] relation_name
    # @return [Nil]
    private def define_enum_scopes(relation_name)
      reflection = find_reflection_by_name!(relation_name)
      if enum_table_exists?(reflection)
        reflection.klass.names.each do |name|
          scope name, -> { public_send("with_#{reflection.name}", name) }
          scope "not_#{name}", -> { public_send("exclude_#{reflection.name}", name) }
        end
      end
    end

    # Finds a reflection by name
    # @param [Symbol] relation_name
    # @raise [ArgumentError]
    # @return [PowerEnum::Reflection::EnumerationReflection]
    private def find_reflection_by_name!(relation_name)
      reflection = reflect_on_all_associations(:belongs_to).find { |relation| relation.name == relation_name.to_sym }
      if reflection&.class != PowerEnum::Reflection::EnumerationReflection
        raise ArgumentError, "Relation #{relation_name} doesn't exist"
      end

      reflection
    end

    # Checks if there's a DB connection and if given table exists
    # @param [Symbol] relation_name
    # @return [Boolean]
    private def enum_table_exists?(reflection)
      connection.table_exists?(reflection.plural_name)
    rescue ActiveRecord::NoDatabaseError, PG::ConnectionBad
      false
    end
  end
end

[MityaLiu]

Thank you.

[albertosaurus]

First of all, sorry about the late reply. Otherwise, my big concern with what you're doing is that I think you're forcing enum values to be read at load time.