Shift pseudo-code to Transition Plan section and provide a pseudo-code

implementation of what BaseException will look like in Python 3.0 .

pep-0352.txt

@@ -2,7 +2,8 @@ PEP: 352
 Title: Required Superclass for Exceptions
 Version: $Revision$
 Last-Modified: $Date$
-Author: Brett Cannon <brett@python.org>, Guido van Rossum <guido@python.org>
+Author: Brett Cannon <brett@python.org>
+        Guido van Rossum <guido@python.org>
 Status: Final
 Type: Standards Track
 Content-Type: text/x-rst
@@ -53,70 +54,36 @@ Requiring a Common Superclass
 
 This PEP proposes introducing a new exception named BaseException that
 is a new-style class and has a single attribute, ``message`` (that
-will cause the deprecation of the existing ``args`` attribute)::
+will cause the deprecation of the existing ``args`` attribute)  Below
+is the code as the exception will work in Python 3.0 (how it will
+work in Python 2.x is covered in the `Transition Plan`_ section)::
 
   class BaseException(object):
 
       """Superclass representing the base of the exception hierarchy.
 
-      Provides a 'message' attribute that contains any single argument
-      passed in during instantiation.  If more than one argument is passed, it
-      is set to the empty string.  It is meant to represent any message
-      (usually some text) that should be printed out with the traceback.
-      Unfortunately, for backwards-compatibility, the 'args' attribute
-      (discussed below) is used for printing out to tracebacks.
-
-      The 'args' attribute and __getitem__ method are provided for
-      backwards-compatibility and will be deprecated at some point.
+      Provides a 'message' attribute that contains either the single
+      argument to the constructor or the empty string.  This attribute
+      is used in both the string and unicode representation for the
+      exception.  This is so that it provides the extra details in the
+      traceback.
 
       """
 
-      def __init__(self, *args):
-          """Set 'message' and 'args' attribute.
-
-	  'args' will eventually be deprecated.  But it is still used when
-	  printing out tracebacks for backwards-compatibility.  Once 'args' is
-	  removed, though, 'message' will be used instead.
-
-	  """
-          self.args = args
-          self.message = args[0] if args else ''
+      def __init__(self, message=''):
+          """Set the 'message' attribute'"""
+          self.message = message
 
       def __str__(self):
-          """Return the str of args[0] or args, depending on length.
-	  
-	  Once 'args' has been removed, 'message' will be used exclusively for
-	  the str representation for exceptions.
-	  
-	  """
-          return str(self.args[0]
-                     if len(self.args) <= 1
-                     else self.args)
+          """Return the str of 'message'"""
+          return str(self.message)
 
       def __unicode__(self):
-          """Return the unicode of args[0] or args, depending on length.
-
-	  Once 'args' has been removed, 'message' will be used exclusively for
-	  the unicode representation of exceptions.
-
-	  """
-          return unicode(self.args[0]
-                         if len(self.args) <= 1
-                         else self.args)
+          """Return the unicode of 'message'"""
+          return unicode(self.message)
 
       def __repr__(self):
-          func_args = repr(self.args) if self.args else "()"
-          return self.__class__.__name__ + func_args
-
-      def __getitem__(self, index):
-          """Index into arguments passed in during instantiation.
-
-          Provided for backwards-compatibility and will be
-          deprecated.
-
-          """
-          return self.args[index]
-
+          return "%s(%s)" % (self.__class__.__name__, repr(self.message))
 
 The ``message`` attribute will contain either the first argument
 passed in at instantiation of the object or the empty string if no
@@ -212,6 +179,72 @@ semantics starting in the version following the introduction of the
 deprecation and the raising of a DeprecationWarning for the version
 specifically listed.
 
+Here is BaseException as implemented in the 2.x series::
+
+  class BaseException(object):
+
+      """Superclass representing the base of the exception hierarchy.
+
+      Provides a 'message' attribute that contains any single argument
+      passed in during instantiation.  If more than one argument is
+      passed, it is set to the empty string.  It is meant to represent
+      any message (usually some text) that should be printed out with
+      the traceback.  Unfortunately, for backwards-compatibility, the
+      'args' attribute (discussed below) is used for printing out to
+      tracebacks.
+
+      The 'args' attribute and __getitem__ method are provided for
+      backwards-compatibility and will be deprecated at some point.
+
+      """
+
+      def __init__(self, *args):
+          """Set 'message' and 'args' attribute.
+
+          'args' will eventually be deprecated.  But it is still used
+          when printing out tracebacks for backwards-compatibility.
+          Once 'args' is removed, though, 'message' will be used instead.
+
+          """
+          self.args = args
+          self.message = args[0] if args else ''
+
+      def __str__(self):
+          """Return the str of args[0] or args, depending on length.
+  
+          Once 'args' has been removed, 'message' will be used
+          exclusively for the str representation for exceptions.
+  
+          """
+          return str(self.args[0]
+                     if len(self.args) <= 1
+                     else self.args)
+
+      def __unicode__(self):
+          """Return the unicode of args[0] or args, depending on length.
+
+          Once 'args' has been removed, 'message' will be used
+          exclusively for the unicode representation of exceptions.
+
+          """
+          return unicode(self.args[0]
+                         if len(self.args) <= 1
+                         else self.args)
+
+      def __repr__(self):
+          func_args = repr(self.args) if self.args else "()"
+          return self.__class__.__name__ + func_args
+
+      def __getitem__(self, index):
+          """Index into arguments passed in during instantiation.
+
+          Provided for backwards-compatibility and will be
+          deprecated.
+
+          """
+          return self.args[index]
+
+
 Deprecation of features in Python 2.9 is optional.  This is because it
 is not known at this time if Python 2.9 (which is slated to be the
 last version in the 2.x series) will actively deprecate features that