# HG changeset patch
# User Paul Boddie <paul@boddie.org.uk>
# Date 1241826342 -7200
# Node ID 6bcd2a7c7a2ae7b8fad879658ebbd469d809e41c
# Parent  eb198a981723ad3be887724e530373bc0242de86
Reorganised the instance attribute positioning methods.

diff -r eb198a981723 -r 6bcd2a7c7a2a micropython/data.py
--- a/micropython/data.py	Tue May 05 20:25:51 2009 +0200
+++ b/micropython/data.py	Sat May 09 01:45:42 2009 +0200
@@ -751,42 +751,52 @@
 
         "Make sure that the instance attributes are fully defined."
 
-        if self.all_instattr is None:
-            self.all_instattr = {}
-            instattr = {}
-
-            # Record provisional position information for attributes of this
-            # instance.
-
-            for name in self.instattr:
-                instattr[name] = set() # position not yet defined
-
-            reversed_bases = self.bases[:]
-            reversed_bases.reverse()
-
-            # For the bases in reverse order, acquire instance attribute
-            # details.
+        # Cache the attributes by converting the positioned attributes into a
+        # dictionary.
 
-            for cls in reversed_bases:
-                for name, attr in cls.instance_attributes().items():
-
-                    # Record previous attribute information.
-
-                    if instattr.has_key(name):
-                        instattr[name].add(attr.position)
-
-            # Cache the attributes by converting the positioned attributes into
-            # a dictionary.
-
-            if not instattr:
-                self.all_instattr = {}
-            else:
-                self.all_instattr = self._get_attributes(instattr)
-
+        if self.all_instattr is None:
+            self.all_instattr = self._get_attributes()
             self.all_instattr_names = self.all_instattr.keys()
 
         return self.all_instattr
 
+    def _get_attributes(self):
+
+        """
+        Return a dictionary mapping names to Attr instances incorporating
+        information about their positions in the final instance structure.
+        """
+
+        instattr = {}
+
+        # Record provisional position information for attributes of this
+        # instance.
+
+        for name in self.instattr:
+            instattr[name] = set() # position not yet defined
+
+        reversed_bases = self.bases[:]
+        reversed_bases.reverse()
+
+        # For the bases in reverse order, acquire instance attribute
+        # details.
+
+        for cls in reversed_bases:
+            for name, attr in cls.instance_attributes().items():
+
+                # Record previous attribute information.
+
+                if instattr.has_key(name):
+                    instattr[name].add(attr.position)
+
+        # Build the dictionary of attributes using the existing positions known
+        # for each name.
+
+        d = {}
+        for i, name in enumerate(self._get_position_list(instattr)):
+            d[name] = Attr(i, Instance(), name)
+        return d
+
     def _get_position_list(self, positions):
 
         """
@@ -827,19 +837,6 @@
         #print "->", namearray
         return namearray
 
-    def _get_attributes(self, positions):
-
-        """
-        For the given 'positions' mapping from names to positions, return a
-        dictionary mapping names to Attr instances incorporating information
-        about their positions in the final instance structure.
-        """
-
-        d = {}
-        for i, name in enumerate(self._get_position_list(positions)):
-            d[name] = Attr(i, Instance(), name)
-        return d
-
     def _cmp_positions(self, a, b):
 
         "Compare name plus position list operands 'a' and 'b'."
@@ -1050,9 +1047,16 @@
         Defaults are also finalised by this method.
         """
 
+        if self.finalised:
+            return
+
+        # Defaults.
+
         for i, default in enumerate(self.default_attrs):
             default.position = i
 
+        # Locals.
+
         i = None
         for i, name in enumerate(self.argnames):
             self[name].position = i