Initial attempt at hoisting type annotations from the descriptors to …

…the containing class.

marrow/schema/declarative.py

@@ -110,8 +110,13 @@ class DataAttribute(Element):
 	The base attribute class which implements the descriptor protocol, pulling the instance value of the attribute from
 	the containing object's ``__data__`` dictionary.  If an attempt is made to read an attribute that does not have a
 	corresponding value in the data dictionary an ``AttributeError`` will be raised.
+	
+	Python type annotations relating to the value read/written on instances may be declared as the `annotation`. This
+	will be used to populate the class `__annotations__` for any class an instance of this is assigned to.
 	"""
 
+	annotation = None
+
 	def __get__(self, obj, cls=None):
 		"""Executed when retrieving a DataAttribute instance attribute."""
 

marrow/schema/meta.py

@@ -86,6 +86,8 @@ def process(name, attr):
 		# Iteratively process the Element subclass instances and update their definition.
 		attributes.update(process(k, v) for k, v in attrs.items() if isinstance(v, Element))
 		attrs['__attributes__'] = odict(sorted(attributes.items(), key=lambda t: t[1].__sequence__))
+		attrs.setdefault('__annotations__', dict())
+		attrs['__annotations__'].update({k: v.annotation for k, v in attributes.items() if hasattr(v, 'annotation')})
 
 		# Construct the new class.
 		cls = type.__new__(meta, str(name), bases, attrs)