add some comments.

sim/pyconfig/m5config.py:
    Add some comments to indicate what the decorators mean.

--HG--
extra : convert_revision : fbcbcbe4ad8cd62f2bd12af6b1f141c66752b870

sim/pyconfig/m5config.py

@@ -234,6 +234,9 @@ class MetaConfigNode(type):
         for key,val in dict.items():
             del dict[key]
 
+            # See description of decorators in the importer.py file
+            # We just strip off the expr_decorator now since we don't
+            # need from this point on.
             if key.startswith(expr_decorator):
                 key = key[len(expr_decorator):]
 
@@ -285,6 +288,9 @@ class MetaConfigNode(type):
 
         # initialize attributes with values from class definition
         for key,value in dict.iteritems():
+            # turn an expression that was munged in the importer
+            # because it had dots into a list so that we can find the
+            # proper variable to modify.
             key = key.split(dot_decorator)
             c = cls
             for item in key[:-1]: