Module: Mixins::Delegation

Defined in:
lib/mixins/delegation.rb

Overview

A collection of various delegation code-generators that can be used to define delegation through other methods, to instance variables, etc.

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.make_ivar_delegator(ivar_name, name) ⇒ Object

Make the body of a delegator method that will delegate calls to the name method to the given ivar.



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# File 'lib/mixins/delegation.rb', line 84

def make_ivar_delegator( ivar_name, name )
	return ->( *args, **kwargs, &block ) do
		ivar = self.instance_variable_get( ivar_name )
		ivar.__send__( name, *args, **kwargs, &block )
	rescue => err
		bt = err.backtrace_locations
		bt.shift
		raise( err, err.message, bt, cause: err )
	end
end

.make_method_delegator(delegate, name) ⇒ Object

Make the body of a delegator method that will delegate to the name method of the object returned by the delegate method.



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# File 'lib/mixins/delegation.rb', line 71

def make_method_delegator( delegate, name )
	return ->( *args, **kwargs, &block ) do
		self.__send__( delegate ).__send__( name, *args, **kwargs, &block )
	rescue => err
		bt = err.backtrace_locations
		bt.shift
		raise( err, err.message, bt, cause: err )
	end
end

Instance Method Details

#def_class_delegators(*delegated_methods) ⇒ Object

Define the given delegated_methods as delegators to the like-named class method.



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# File 'lib/mixins/delegation.rb', line 56

def def_class_delegators( *delegated_methods )
	delegated_methods.each do |name|
		define_method( name ) do |*args|
			self.class.__send__( name, *args )
		end
	end
end

#def_ivar_delegators(ivar, *delegated_methods) ⇒ Object

Define the given delegated_methods as delegators to the like-named method of the specified ivar. This is pretty much identical with how ‘Forwardable’ from the stdlib does delegation, but it’s reimplemented here for consistency.

class MyClass
  extend Mixins::Delegation

  # Delegate the #each method to the @collection ivar
  def_ivar_delegators :@collection, :each

end



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# File 'lib/mixins/delegation.rb', line 46

def def_ivar_delegators( ivar, *delegated_methods )
	delegated_methods.each do |name|
		body = Mixins::Delegation.make_ivar_delegator( ivar, name )
		define_method( name, &body )
	end
end

#def_method_delegators(delegate_method, *delegated_methods) ⇒ Object

Define the given delegated_methods as delegators to the like-named method of the return value of the delegate_method.

class MyClass
  extend Mixins::Delegation

  # Delegate the #bound?, #err, and #result2error methods to the connection
  # object returned by the #connection method. This allows the connection
  # to still be loaded on demand/overridden/etc.
  def_method_delegators :connection, :bound?, :err, :result2error

  def connection
    @connection ||= self.connect
  end
end



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# File 'lib/mixins/delegation.rb', line 26

def def_method_delegators( delegate_method, *delegated_methods )
	delegated_methods.each do |name|
		body = Mixins::Delegation.make_method_delegator( delegate_method, name )
		define_method( name, &body )
	end
end