operation.py: Refactor `polswitch' a little.

We're going to use this structure again.

diff --git a/operation.py b/operation.py
index 1184e3d..e10a1b5 100644 (file)
--- a/operation.py
+++ b/operation.py
@@ -41,6 +41,16 @@ import util as U
 ### password.)
 
 ###--------------------------------------------------------------------------
+### Some utilities.
+
+OPS = ['set', 'reset', 'clear']
+## A list of the available operations.
+
+class polswitch (U.struct):
+  """A small structure holding a value for each operation."""
+  __slots__ = OPS
+
+###--------------------------------------------------------------------------
 ### Operation protocol.
 
 ## An operation deals with a single service/user pair.  The protocol works
@@ -243,14 +253,11 @@ CONF.export('ClearRequest')
 ###--------------------------------------------------------------------------
 ### Master policy switch.
 
-class polswitch (U.struct):
-  __slots__ = ['set', 'reset', 'clear']
-
 CONF.DEFAULTS.update(
 
   ## Map a request type `set', `reset', or `clear', to the appropriate
   ## request class.
-  RQCLASS = polswitch(None, None, None),
+  RQCLASS = polswitch(**dict((i, None) for i in OPS)),
 
   ## Alternatively, set this to a mixin class to apply common policy to all
   ## the kinds of requests.