Parrot's Class.attributes method no longer returns attribute

names in the same order in which they were declared (indeed,
the order is somewhat unpredictable).  Since we need to initialize
attributes in the order they were declared, add a @!attribute_list
property and 'attriter' method to the Class PMC that allows Rakudo
keep track of the order in which attributes are declared.

src/builtins/guts.pir

@@ -704,6 +704,12 @@ and C<type>.
     $I0 = exists $P0[name]
     if $I0 goto attr_exists
     addattribute metaclass, name
+    $P1 = getprop '@!attribute_list', metaclass
+    unless null $P1 goto have_attrlist
+    $P1 = root_new ['parrot';'ResizableStringArray']
+    setprop metaclass, '@!attribute_list', $P1
+  have_attrlist:
+    push $P1, name
     $P0 = metaclass.'attributes'()
   attr_exists:
 

src/classes/Object.pir

@@ -44,7 +44,7 @@ like this.
     parrotclass = p6meta.'get_parrotclass'(result)
     if null parrotclass goto attrinit_done
     attributes = inspect parrotclass, 'attributes'
-    it = iter attributes
+    it = parrotclass.'attriter'()
   attrinit_loop:
     unless it goto attrinit_done
     .local string attrname, shortname
@@ -298,7 +298,7 @@ the object's type and address.
     parentproto = find_caller_lex '$CLASS'
     parrotclass = p6meta.'get_parrotclass'(parentproto)
     attributes = inspect parrotclass, 'attributes'
-    it = iter attributes
+    it = parrotclass.'attriter'()
   attrinit_loop:
     unless it goto attrinit_done
     .local string attrname, keyname
@@ -422,7 +422,7 @@ XXX This had probably best really just tailcall .^CREATE; move this stuff later.
     unless class_it goto classinit_loop_end
     cur_class = shift class_it
     attributes = inspect cur_class, 'attributes'
-    it = iter attributes
+    it = cur_class.'attriter'()
   attrinit_loop:
     unless it goto attrinit_done
     .local string attrname

src/parrot/misc.pir

@@ -80,3 +80,25 @@ Gets the name of the routine.
   done:
     .return ($S0)
 .end
+
+
+=item Class.attriter
+
+Return an iterator that iterates over a Class' attributes.
+If the Class object has a @!attribute_list property, use 
+that as the order of attributes, otherwise introspect the
+class and use its list.  (As of Parrot 1.4.0 we can't
+always introspect the class directly, as the order of
+attributes in the class isn't guaranteed.)
+
+=cut
+
+.namespace ['Class']
+.sub 'attriter' :method
+    $P0 = getprop '@!attribute_list', self
+    unless null $P0 goto have_list
+    $P0 = inspect self, 'attributes'
+  have_list:
+    $P1 = iter $P0
+    .return ($P1)
+.end