[Zope3-checkins] SVN: Zope3/trunk/src/zope/interface/ Fixed bug: the invariants function didn't work as a Python 2.4

[Jim Fulton]

Log message for revision 29899:
  Fixed bug: the invariants function didn't work as a Python 2.4
  decorator.
  

Changed:
  U   Zope3/trunk/src/zope/interface/interface.py
  U   Zope3/trunk/src/zope/interface/tests/test_interface.py

-=-
Modified: Zope3/trunk/src/zope/interface/interface.py
===================================================================
--- Zope3/trunk/src/zope/interface/interface.py	2005-04-07 14:41:10 UTC (rev 29898)
+++ Zope3/trunk/src/zope/interface/interface.py	2005-04-07 17:44:44 UTC (rev 29899)
@@ -29,6 +29,8 @@
 CO_VARKEYWORDS = 8
 TAGGED_DATA = '__interface_tagged_values__'
 
+_decorator_non_return = object()
+
 def invariant(call):
     f_locals = sys._getframe(1).f_locals
     tags = f_locals.get(TAGGED_DATA)
@@ -38,6 +40,7 @@
     if invariants is None:
         invariants = tags['invariants'] = []
     invariants.append(call)
+    return _decorator_non_return
 
 class Element(object):
 
@@ -448,6 +451,8 @@
                     attr.__name__ = name
             elif isinstance(attr, FunctionType):
                 attrs[name] = fromFunction(attr, self, name=name)
+            elif attr is _decorator_non_return:
+                del attrs[name]
             else:
                 raise InvalidInterface("Concrete attribute, %s" %name)
 

Modified: Zope3/trunk/src/zope/interface/tests/test_interface.py
===================================================================
--- Zope3/trunk/src/zope/interface/tests/test_interface.py	2005-04-07 14:41:10 UTC (rev 29898)
+++ Zope3/trunk/src/zope/interface/tests/test_interface.py	2005-04-07 17:44:44 UTC (rev 29899)
@@ -15,12 +15,14 @@
 
 $Id$
 """
+import sys
 import unittest
 from zope.testing.doctestunit import DocTestSuite
 from zope.interface.tests.unitfixtures import *  # hehehe
 from zope.interface.exceptions import BrokenImplementation, Invalid
 from zope.interface import implementedBy, providedBy
 from zope.interface import Interface, directlyProvides, Attribute
+from zope import interface
 
 class InterfaceTests(unittest.TestCase):
 
@@ -278,10 +280,44 @@
     f23 = f22
 
 
+
+if sys.version_info >= (2, 4):
+    def test_invariant_as_decorator():
+        """Invaiants can be deined in line
+
+          >>> class IRange(interface.Interface):
+          ...     min = interface.Attribute("Lower bound")
+          ...     max = interface.Attribute("Upper bound")
+          ...
+          ...     @interface.invariant
+          ...     def range_invariant(ob):
+          ...         if ob.max < ob.min:
+          ...             raise Invalid('max < min')
+
+
+          >>> class Range(object):
+          ...     interface.implements(IRange)
+          ...
+          ...     def __init__(self, min, max):
+          ...         self.min, self.max = min, max
+
+          >>> IRange.validateInvariants(Range(1,2))
+          >>> IRange.validateInvariants(Range(1,1))
+          >>> IRange.validateInvariants(Range(2,1))
+          Traceback (most recent call last):
+          ...
+          Invalid: max < min
+
+
+        """
+
+
 def test_suite():
     from zope.testing import doctest
     suite = unittest.makeSuite(InterfaceTests)
     suite.addTest(doctest.DocTestSuite("zope.interface.interface"))
+    if sys.version_info >= (2, 4):
+        suite.addTest(doctest.DocTestSuite())
     suite.addTest(doctest.DocFileSuite(
         '../README.txt',
         globs={'__name__': '__main__'},