--- a/bGrease/world.py	Wed Sep 21 15:43:12 2011 +0200
+++ b/bGrease/world.py	Wed Sep 21 16:10:14 2011 +0200
@@ -1,302 +1,301 @@
-#############################################################################
-#
-# Copyright (c) 2010 by Casey Duncan and contributors
-# All Rights Reserved.
-#
-# This software is subject to the provisions of the MIT License
-# A copy of the license should accompany this distribution.
-# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
-#
-#############################################################################
-"""Worlds are environments described by a configuration of components, systems and 
-renderers. These parts describe the data, behavioral and presentation aspects
-of the world respectively.
-
-The world environment is the context within which entities exist. A typical
-application consists of one or more worlds containing entities that evolve
-over time and react to internal and external interaction.
-
-See :ref:`an example of world configuration in the tutorial <tut-world-example>`.
-"""
-
-__version__ = '$Id$'
-
-import itertools
-from bGrease import mode
-from bGrease.component import ComponentError
-from bGrease.entity import Entity, ComponentEntitySet
-
-
-class BaseWorld(object):
-	"""A coordinated collection of components, systems and entities
-	
-	A world is also a mode that may be pushed onto a 
-	:class:`grease.mode.Manager`
-	"""
-
-	components = None
-	""":class:`ComponentParts` object containing all world components.
-	:class:`grease.component.Component` objects define and contain all entity data
-	"""
-
-	systems = None
-	""":class:`Parts` object containing all world systems. 
-	:class:`grease.System` objects define world and entity behavior
-	"""
-
-	renderers = None
-	""":class:`Parts` object containing all world renderers. 
-	:class:`grease.Renderer` objects define world presentation
-	"""
-
-	entities = None
-	"""Set of all entities that exist in the world"""
-
-	def __init__(self):
-		self.components = ComponentParts(self)
-		self.systems = Parts(self)
-		self.renderers = Parts(self)
-		self.new_entity_id = itertools.count().next
-		self.new_entity_id() # skip id 0
-		self.entities = WorldEntitySet(self)
-		self._full_extent = EntityExtent(self, self.entities)
-		self._extents = {}
-		self.configure()
-
-	def configure(self):
-		"""Hook to configure the world after construction. This method
-		is called immediately after the world is initialized. Override
-		in a subclass to configure the world's components, systems,
-		and renderers.
-
-		The default implementation does nothing.
-		"""
-	
-	def __getitem__(self, entity_class):
-		"""Return an :class:`EntityExtent` for the given entity class. This extent
-		can be used to access the set of entities of that class in the world
-		or to query these entities via their components. 
-
-		Examples::
-
-			world[MyEntity]
-			world[...]
-
-		:param entity_class: The entity class for the extent.
-
-			May also be a tuple of entity classes, in which case
-			the extent returned contains union of all entities of the classes
-			in the world.
-
-			May also be the special value ellipsis (``...``), which
-			returns an extent containing all entities in the world.  This allows
-			you to conveniently query all entities using ``world[...]``.
-		"""
-		if isinstance(entity_class, tuple):
-			entities = set()
-			for cls in entity_class:
-				if cls in self._extents:
-					entities |= self._extents[cls].entities
-			return EntityExtent(self, entities)
-		elif entity_class is Ellipsis:
-			return self._full_extent
-		try:
-			return self._extents[entity_class]
-		except KeyError:
-			extent = self._extents[entity_class] = EntityExtent(self, set())
-			return extent
-	
-	def draw_renderers(self):
-		"""Draw all renderers"""
-		for renderer in self.renderers:
-			renderer.draw()
-
-class WorldEntitySet(set):
-	"""Entity set for a :class:`World`"""
-
-	def __init__(self, world):
-		self.world = world
-	
-	def add(self, entity):
-		"""Add the entity to the set and all necessary class sets
-		Return the unique entity id for the entity, creating one
-		as needed.
-		"""
-		super(WorldEntitySet, self).add(entity)
-		for cls in entity.__class__.__mro__:
-			if issubclass(cls, Entity):
-				self.world[cls].entities.add(entity)
-
-	def remove(self, entity):
-		"""Remove the entity from the set and, world components,
-		and all necessary class sets
-		"""
-		super(WorldEntitySet, self).remove(entity)
-		for component in self.world.components:
-			try:
-				del component[entity]
-			except KeyError:
-				pass
-		for cls in entity.__class__.__mro__:
-			if issubclass(cls, Entity):
-				self.world[cls].entities.discard(entity)
-	
-	def discard(self, entity):
-		"""Remove the entity from the set if it exists, if not,
-		do nothing
-		"""
-		try:
-			self.remove(entity)
-		except KeyError:
-			pass
-
-
-class EntityExtent(object):
-	"""Encapsulates a set of entities queriable by component. Extents
-	are accessed by using an entity class as a key on the :class:`World`::
-
-		extent = world[MyEntity]
-	"""
-
-	entities = None
-	"""The full set of entities in the extent""" 
-
-	def __init__(self, world, entities):
-		self.__world = world
-		self.entities = entities
-
-	def __getattr__(self, name):
-		"""Return a queriable :class:`ComponentEntitySet` for the named component 
-
-		Example::
-
-			world[MyEntity].movement.velocity > (0, 0)
-
-		Returns a set of entities where the value of the :attr:`velocity` field
-		of the :attr:`movement` component is greater than ``(0, 0)``.
-		"""
-		component = getattr(self.__world.components, name)
-		return ComponentEntitySet(component, self.entities & component.entities)
-
-
-class Parts(object):
-	"""Maps world parts to attributes. The parts are kept in the
-	order they are set. Parts may also be inserted out of order.
-	
-	Used for:
-	
-	- :attr:`World.systems`
-	- :attr:`World.renderers`
-	"""
-
-	_world = None
-	_parts = None
-	_reserved_names = ('entities', 'entity_id', 'world')
-
-	def __init__(self, world):
-		self._world = world
-		self._parts = []
-	
-	def _validate_name(self, name):
-		if (name in self._reserved_names or name.startswith('_') 
-			or hasattr(self.__class__, name)):
-			raise ComponentError('illegal part name: %s' % name)
-		return name
-
-	def __setattr__(self, name, part):
-		if not hasattr(self.__class__, name):
-			self._validate_name(name)
-			if not hasattr(self, name):
-				self._parts.append(part)
-			else:
-				old_part = getattr(self, name)
-				self._parts[self._parts.index(old_part)] = part
-			super(Parts, self).__setattr__(name, part)
-			if hasattr(part, 'set_world'):
-				part.set_world(self._world)
-		elif name.startswith("_"):
-			super(Parts, self).__setattr__(name, part)
-		else:
-			raise AttributeError("%s attribute is read only" % name)
-	
-	def __delattr__(self, name):
-		self._validate_name(name)
-		part = getattr(self, name)
-		self._parts.remove(part)
-		super(Parts, self).__delattr__(name)
-
-	def insert(self, name, part, before=None, index=None):
-		"""Add a part with a particular name at a particular index.
-		If a part by that name already exists, it is replaced.
-			
-		:arg name: The name of the part.
-		:type name: str
-
-		:arg part: The component, system, or renderer part to insert
-	
-		:arg before: A part object or name. If specified, the part is
-			inserted before the specified part in order.
-
-		:arg index: If specified, the part is inserted in the position
-			specified. You cannot specify both before and index.
-		:type index: int
-		"""
-		assert before is not None or index is not None, (
-			"Must specify a value for 'before' or 'index'")
-		assert before is None or index is None, (
-			"Cannot specify both 'before' and 'index' arguments when inserting")
-		self._validate_name(name)
-		if before is not None:
-			if isinstance(before, str):
-				before = getattr(self, before)
-			index = self._parts.index(before)
-		if hasattr(self, name):
-			old_part = getattr(self, name)
-			self._parts.remove(old_part)
-		self._parts.insert(index, part)
-		super(Parts, self).__setattr__(name, part)
-		if hasattr(part, 'set_world'):
-			part.set_world(self._world)
-
-	def __iter__(self):
-		"""Iterate the parts in order"""
-		return iter(tuple(self._parts))
-	
-	def __len__(self):
-		return len(self._parts)
-
-
-class ComponentParts(Parts):
-	"""Maps world components to attributes. The components are kept in the
-	order they are set. Components may also be inserted out of order.
-
-	Used for: :attr:`World.components`
-	"""
-
-	def join(self, *component_names):
-		"""Join and iterate entity data from multiple components together.
-
-		For each entity in all of the components named, yield a tuple containing
-		the entity data from each component specified.
-
-		This is useful in systems that pull data from multiple components.
-		
-		Typical Usage::
-
-			for position, movement in world.components.join("position", "movement"):
-				# Do something with each entity's position and movement data
-		"""
-		if component_names:
-			components = [getattr(self, self._validate_name(name)) 
-				for name in component_names]
-			if len(components) > 1:
-				entities = components[0].entities & components[1].entities
-				for comp in components[2:]:
-					entities &= comp.entities
-			else:
-				entities = components[0].entities
-			for entity in entities:
-				yield tuple(comp[entity] for comp in components)
-
+#############################################################################
+#
+# Copyright (c) 2010 by Casey Duncan and contributors
+# All Rights Reserved.
+#
+# This software is subject to the provisions of the MIT License
+# A copy of the license should accompany this distribution.
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+#
+#############################################################################
+"""Worlds are environments described by a configuration of components, systems and 
+renderers. These parts describe the data, behavioral and presentation aspects
+of the world respectively.
+
+The world environment is the context within which entities exist. A typical
+application consists of one or more worlds containing entities that evolve
+over time and react to internal and external interaction.
+
+See :ref:`an example of world configuration in the tutorial <tut-world-example>`.
+"""
+
+__version__ = '$Id$'
+
+import itertools
+from parpg.bGrease import mode
+from parpg.bGrease.component import ComponentError
+from parpg.bGrease.entity import Entity, ComponentEntitySet
+
+
+class BaseWorld(object):
+        """A coordinated collection of components, systems and entities
+
+        A world is also a mode that may be pushed onto a 
+        :class:`grease.mode.Manager`
+        """
+
+        components = None
+        """:class:`ComponentParts` object containing all world components.
+	:class:`grease.component.Component` objects define and contain all entity data
+	"""
+
+        systems = None
+        """:class:`Parts` object containing all world systems. 
+	:class:`grease.System` objects define world and entity behavior
+	"""
+
+        renderers = None
+        """:class:`Parts` object containing all world renderers. 
+	:class:`grease.Renderer` objects define world presentation
+	"""
+
+        entities = None
+        """Set of all entities that exist in the world"""
+
+        def __init__(self):
+                self.components = ComponentParts(self)
+                self.systems = Parts(self)
+                self.renderers = Parts(self)
+                self.new_entity_id = itertools.count().next
+                self.new_entity_id() # skip id 0
+                self.entities = WorldEntitySet(self)
+                self._full_extent = EntityExtent(self, self.entities)
+                self._extents = {}
+                self.configure()
+
+        def configure(self):
+                """Hook to configure the world after construction. This method
+                is called immediately after the world is initialized. Override
+                in a subclass to configure the world's components, systems,
+                and renderers.
+
+                The default implementation does nothing.
+                """
+
+        def __getitem__(self, entity_class):
+                """Return an :class:`EntityExtent` for the given entity class. This extent
+                can be used to access the set of entities of that class in the world
+                or to query these entities via their components. 
+
+                Examples::
+
+                	world[MyEntity]
+                	world[...]
+
+                :param entity_class: The entity class for the extent.
+
+                	May also be a tuple of entity classes, in which case
+                	the extent returned contains union of all entities of the classes
+                	in the world.
+
+                	May also be the special value ellipsis (``...``), which
+                	returns an extent containing all entities in the world.  This allows
+                	you to conveniently query all entities using ``world[...]``.
+                """
+                if isinstance(entity_class, tuple):
+                        entities = set()
+                        for cls in entity_class:
+                                if cls in self._extents:
+                                        entities |= self._extents[cls].entities
+                        return EntityExtent(self, entities)
+                elif entity_class is Ellipsis:
+                        return self._full_extent
+                try:
+                        return self._extents[entity_class]
+                except KeyError:
+                        extent = self._extents[entity_class] = EntityExtent(self, set())
+                        return extent
+
+        def draw_renderers(self):
+                """Draw all renderers"""
+                for renderer in self.renderers:
+                        renderer.draw()
+
+class WorldEntitySet(set):
+        """Entity set for a :class:`World`"""
+
+        def __init__(self, world):
+                self.world = world
+
+        def add(self, entity):
+                """Add the entity to the set and all necessary class sets
+                Return the unique entity id for the entity, creating one
+                as needed.
+                """
+                super(WorldEntitySet, self).add(entity)
+                for cls in entity.__class__.__mro__:
+                        if issubclass(cls, Entity):
+                                self.world[cls].entities.add(entity)
+
+        def remove(self, entity):
+                """Remove the entity from the set and, world components,
+                and all necessary class sets
+                """
+                super(WorldEntitySet, self).remove(entity)
+                for component in self.world.components:
+                        try:
+                                del component[entity]
+                        except KeyError:
+                                pass
+                for cls in entity.__class__.__mro__:
+                        if issubclass(cls, Entity):
+                                self.world[cls].entities.discard(entity)
+
+        def discard(self, entity):
+                """Remove the entity from the set if it exists, if not,
+                do nothing
+                """
+                try:
+                        self.remove(entity)
+                except KeyError:
+                        pass
+
+
+class EntityExtent(object):
+        """Encapsulates a set of entities queriable by component. Extents
+        are accessed by using an entity class as a key on the :class:`World`::
+
+        	extent = world[MyEntity]
+        """
+
+        entities = None
+        """The full set of entities in the extent""" 
+
+        def __init__(self, world, entities):
+                self.__world = world
+                self.entities = entities
+
+        def __getattr__(self, name):
+                """Return a queriable :class:`ComponentEntitySet` for the named component 
+
+                Example::
+
+                	world[MyEntity].movement.velocity > (0, 0)
+
+                Returns a set of entities where the value of the :attr:`velocity` field
+                of the :attr:`movement` component is greater than ``(0, 0)``.
+                """
+                component = getattr(self.__world.components, name)
+                return ComponentEntitySet(component, self.entities & component.entities)
+
+
+class Parts(object):
+        """Maps world parts to attributes. The parts are kept in the
+        order they are set. Parts may also be inserted out of order.
+
+        Used for:
+
+        - :attr:`World.systems`
+        - :attr:`World.renderers`
+        """
+
+        _world = None
+        _parts = None
+        _reserved_names = ('entities', 'entity_id', 'world')
+
+        def __init__(self, world):
+                self._world = world
+                self._parts = []
+
+        def _validate_name(self, name):
+                if (name in self._reserved_names or name.startswith('_') 
+                    or hasattr(self.__class__, name)):
+                        raise ComponentError('illegal part name: %s' % name)
+                return name
+
+        def __setattr__(self, name, part):
+                if not hasattr(self.__class__, name):
+                        self._validate_name(name)
+                        if not hasattr(self, name):
+                                self._parts.append(part)
+                        else:
+                                old_part = getattr(self, name)
+                                self._parts[self._parts.index(old_part)] = part
+                        super(Parts, self).__setattr__(name, part)
+                        if hasattr(part, 'set_world'):
+                                part.set_world(self._world)
+                elif name.startswith("_"):
+                        super(Parts, self).__setattr__(name, part)
+                else:
+                        raise AttributeError("%s attribute is read only" % name)
+
+        def __delattr__(self, name):
+                self._validate_name(name)
+                part = getattr(self, name)
+                self._parts.remove(part)
+                super(Parts, self).__delattr__(name)
+
+        def insert(self, name, part, before=None, index=None):
+                """Add a part with a particular name at a particular index.
+                If a part by that name already exists, it is replaced.
+
+                :arg name: The name of the part.
+                :type name: str
+
+                :arg part: The component, system, or renderer part to insert
+
+                :arg before: A part object or name. If specified, the part is
+                	inserted before the specified part in order.
+
+                :arg index: If specified, the part is inserted in the position
+                	specified. You cannot specify both before and index.
+                :type index: int
+                """
+                assert before is not None or index is not None, (
+                        "Must specify a value for 'before' or 'index'")
+                assert before is None or index is None, (
+                        "Cannot specify both 'before' and 'index' arguments when inserting")
+                self._validate_name(name)
+                if before is not None:
+                        if isinstance(before, str):
+                                before = getattr(self, before)
+                        index = self._parts.index(before)
+                if hasattr(self, name):
+                        old_part = getattr(self, name)
+                        self._parts.remove(old_part)
+                self._parts.insert(index, part)
+                super(Parts, self).__setattr__(name, part)
+                if hasattr(part, 'set_world'):
+                        part.set_world(self._world)
+
+        def __iter__(self):
+                """Iterate the parts in order"""
+                return iter(tuple(self._parts))
+
+        def __len__(self):
+                return len(self._parts)
+
+
+class ComponentParts(Parts):
+        """Maps world components to attributes. The components are kept in the
+        order they are set. Components may also be inserted out of order.
+
+        Used for: :attr:`World.components`
+        """
+
+        def join(self, *component_names):
+                """Join and iterate entity data from multiple components together.
+
+                For each entity in all of the components named, yield a tuple containing
+                the entity data from each component specified.
+
+                This is useful in systems that pull data from multiple components.
+
+                Typical Usage::
+
+                	for position, movement in world.components.join("position", "movement"):
+                		# Do something with each entity's position and movement data
+                """
+                if component_names:
+                        components = [getattr(self, self._validate_name(name)) 
+                                      for name in component_names]
+                        if len(components) > 1:
+                                entities = components[0].entities & components[1].entities
+                                for comp in components[2:]:
+                                        entities &= comp.entities
+                        else:
+                                entities = components[0].entities
+                        for entity in entities:
+                                yield tuple(comp[entity] for comp in components)