[Zope3-checkins] CVS: Zope3/src/zope/interface - declarations.py:1.11

[Jim Fulton]

Update of /cvs-repository/Zope3/src/zope/interface
In directory cvs.zope.org:/tmp/cvs-serv20381/src/zope/interface

Modified Files:
	declarations.py 
Log Message:
Added __nonzero__ implementation and test for interface specificationss,


=== Zope3/src/zope/interface/declarations.py 1.10 => 1.11 ===
--- Zope3/src/zope/interface/declarations.py:1.10	Sun Jun  1 18:26:51 2003
+++ Zope3/src/zope/interface/declarations.py	Mon Jun  2 07:07:58 2003
@@ -231,6 +231,32 @@
         self.provides = provides
         self.cls = cls
 
+    def __nonzero__(self):
+        """
+        >>> from zope.interface import Interface
+        >>> class I1(Interface):
+        ...     pass
+        >>> class I2(Interface):
+        ...     pass
+        >>> class C:
+        ...     implements(I1)
+        >>> c = C()
+        >>> int(bool(providedBy(c)))
+        1
+        >>> directlyProvides(c, I2)
+        >>> int(bool(providedBy(c)))
+        1
+        >>> class C:
+        ...     pass
+        >>> c = C()
+        >>> int(bool(providedBy(c)))
+        0
+        >>> directlyProvides(c, I2)
+        >>> int(bool(providedBy(c)))
+        1
+        """
+        return bool(self.__signature__)
+
     def __signature__(self):
 
         provides = self.provides
@@ -416,6 +442,21 @@
         self.set = set
 
         self._computeSignature(iro)
+
+    def __nonzero__(self):
+        """Test whether there are any interfaces in a specification.
+
+        >>> from zope.interface import Interface
+        >>> class I1(Interface): pass
+        ...
+        >>> spec = InterfaceSpecification(I1)
+        >>> int(bool(spec))
+        1
+        >>> spec = InterfaceSpecification()
+        >>> int(bool(spec))
+        0
+        """
+        return bool(self.interfaces)
 
     def _computeSignature(self, iro):
         """Compute a specification signature