Initial revision

intern/python/modules/mcf/utils/hierobj.py

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+'''
+Generic Hierarchic Objects Module
+Hierobj's store their children (which can be anything) in their
+__childlist__ attribute, and provide methods for walking the 
+hierarchy, either collecting results or not.
+
+The index function returns an index of the objects (effectively a
+flattened copy of the hierarchy)
+
+97-03-17 Added ability to pass arguments to hier_rapply and hier_rreturn.
+97-10-31 Removed dependencies on mcf.store
+'''
+import copy,types
+import singletonlist, hier_rx
+
+class Hierobj: 
+	'''
+	An abstract class which handles hierarchic functions and information
+	# remade as a DAG 97-04-02, also reduced memory overhead for
+	hier-r* functions by using while-del-IndexError construct versus
+	for loop (probably makes it slower though)
+	If you require a true hierarchy, use the TrueHierobj class below...
+	'''
+	def __init__(self, parent=None, childlist=None):
+		if parent is None: # passed no parents
+			self.__dict__['__parent__'] = []
+		elif type(parent) == types.ListType: # passed a list of parents
+			self.__dict__['__parent__'] = parent
+		else: # passed a single parent
+			self.__dict__['__parent__'] = [parent]
+		self.__dict__['__childlist__'] = childlist or []
+		for child in self.__childlist__:
+			try:
+				child.__parent__.append(self)
+			except:
+				pass
+	# import simple hierarchic processing methods
+	hier_rapply = hier_rx.hier_rapply
+	hier_rreturn = hier_rx.hier_rreturn
+	hier_rgetattr = hier_rx.hier_rgetattr
+	hier_rmethod = hier_rx.hier_rmethod
+
+
+	def hier_addchild(self, child):
+		'''
+		Add a single child to the childlist
+		'''
+		self.__childlist__.append(child)
+		try:
+			# Hierobj-aware child
+			child.__parent__.append(self) # raises error if not hier_obj aware
+		except (TypeError, AttributeError):
+			# Non Hierobj-aware child
+			pass
+	append = hier_addchild
+	def hier_remchild(self, child):
+		'''
+		Breaks the child relationship with child, including the
+		reciprocal parent relationship
+		'''
+		try:
+			self.__childlist__.remove(child)
+			try:
+				child.hier_remparent(self) # if this fails, no problem
+			except AttributeError: pass
+		except (AttributeError,ValueError):
+			return 0 # didn't manage to remove the child
+		return 1 # succeeded
+	def hier_remparent(self, parent):
+		'''
+		Normally only called by hier_remchild of the parent,
+		just removes the parent from the child's parent list,
+		but leaves child in parent's childlist
+		'''
+		try:
+			self.__parent__.remove(parent)
+		except (AttributeError,ValueError):
+			return 0
+		return 1
+	def hier_replacewith(self,newel):
+		'''
+		As far as the hierarchy is concerned, the new element
+		is exactly the same as the old element, it has all
+		the same children, all the same parents.  The old
+		element becomes completely disconnected from the hierarchy,
+		but it still retains all of its references
+		
+		For every parent, replace this as a child
+		For every child, replace this as the parent
+		'''
+		for parent in self.__parent__:
+			try:
+				parent.hier_replacechild(self, newel)
+			except AttributeError:
+				pass
+		for child in self.__childlist__:
+			try:
+				child.hier_replaceparent(self,parent)
+			except AttributeError:
+				pass
+	def hier_replaceparent(self, oldparent, newparent):
+		ind = self.__parent__.index(oldparent)
+		self.__parent__[ind] = newparent
+	def hier_replacechild(self, oldchild, newchild):
+		ind = self.__childlist__.index(oldchild)
+		self.__childlist__[ind] = newchild
+		
+class TrueHierobj(Hierobj):
+	'''
+	An inefficient implementation of an Hierobj which limits the
+	__parent__ attribute to a single element.  This will likely be
+	_slower_ than an equivalent Hierobj.  That will have to be fixed
+	eventually.
+	'''
+	def __init__(self, parent=None, childlist=[]):
+		if parent is None: # passed no parents
+			self.__dict__['__parent__'] = singletonlist.SingletonList()
+		else: # passed a single parent
+			self.__dict__['__parent__'] = singletonlist.SingletonList(parent)
+		self.__dict__['__childlist__'] = copy.copy(childlist)
+		for child in self.__childlist__:
+			try:
+				child.__parent__.append(self)
+			except:
+				pass
+
+def index(grove):
+	'''
+	Returns a flattened version of the grove
+	'''
+	return grove.hier_rreturn(lambda x: x)
+
+