# Copyright (c) 2011 Edward Langley
 # All rights reserved.
 # 
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions
 # are met:
 # 
 # Redistributions of source code must retain the above copyright notice,
 # this list of conditions and the following disclaimer.
 # 
 # Redistributions in binary form must reproduce the above copyright
 # notice, this list of conditions and the following disclaimer in the
 # documentation and/or other materials provided with the distribution.
 # 
 # Neither the name of the project's author nor the names of its
 # contributors may be used to endorse or promote products derived from
 # this software without specific prior written permission.
 # 
 # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 # "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 # LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 # FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 # HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 # SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
 # TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 # PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 # LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 # NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 # SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 

 import itertools
 def dict_merge(dct1, dct2):
 	commonkeys = set(dct1) & set(dct2)
 	newkeys = set(dct2) - commonkeys
 
 	for key in commonkeys:
 		olditem = dct1[key]
 		newitem = dct2[key]
 		if hasattr(newitem, 'items') and hasattr(olditem, 'items'):
 			dict_merge(olditem, newitem)
 		elif hasattr(olditem, 'update') and hasattr(newitem, '__iter__'):
 			olditem.update(newitem)
 		elif hasattr(olditem, 'extend') and hasattr(newitem, '__iter__'):
 			olditem.extend(newitem)
 		else:
 			dct1[key] = dct2[key]
 	dct1.update( (k,dct2[k]) for k in newkeys )
 	return dct1
 
 
 class _Null: pass
 class Hier(object):
 	####################
 	# Class Attributes #
 	####################
 
 	@classmethod
 	def init(cls):
 		if not hasattr(cls, 'hier'):
 			cls.hier = {}
 
 	@classmethod
 	def from_dict(cls, dct):
 		cls.init()
 		dict_merge(cls.hier, dct)
 		return cls()
 
 	#######################
 	# Instance Attributes #
 	#######################
 
 	def __init__(self, name=''):
 		self.init()
 
 		self._name = name
 
 		self._values = self.hier
 		for segment in self._name.split('.'):
 			item = self._values.get(segment)
 			if hasattr(item, 'items'):
 				print item
 				self._values = item
 			elif name != '':
 				raise ValueError('no such item: %r' % self._name)
 
 	def __getattribute__(self, name):
 		try:
 			return object.__getattribute__(self, name)
 		except AttributeError:
 			if name in self._values:
 				result = self._values[name]
 				if hasattr(result, 'items'):
 					if self._name == '': result = Hier(name)
 					else: result = Hier('%s.%s' % (self._name, name))
 				return result
 			else:
 				raise