metaclass with dynamic creation of properties

Meteclass with dynamic properties creation:

	class DynamicProps( type ):
	"""
	.. class:: DynamicProps
	dynamic creation of properties
	"""
	def __new__( mcs, name, bases, classdict ):
	""" new operator """
	def makeProperty( self, name, value, readOnly=False ):
	""" add property :name: to class
	this also creates a private :_name: attribute
	if you want to make read only property, set :readOnly: flag to True
	:warn: could raise AttributeError if :name: of :_name: is already defined as an attribute
	"""
	fget = lambda self: self._getProperty( name )
	fset = None if readOnly else lambda self, value: self._setProperty( name, value )
	if hasattr( self, "_"+name) or hasattr( self, name ):
	raise AttributeError( "_%s or %s is already defined as a member" % (name, name) )
	setattr( self, '_' + name, value )
	setattr( self.__class__, name, property( fget = fget, fset = fset ) )
	def _setProperty( self, name, value ):
	""" property setter """
	setattr( self, '_' + name, value )
	def _getProperty( self, name ):
	""" property getter """
	return getattr( self, '_' + name )
	classdict["makeProperty"] = makeProperty
	classdict["_setProperty"] = _setProperty
	classdict["_getProperty"] = _getProperty
	return type.__new__( mcs, name, bases, classdict )

view raw DynamicProps.py hosted with ❤ by GitHub

Written as helper class for my graph implementation (metaclass for nodes, edges and graph itself).