# HG changeset patch
# User Jeff Hammel <jhammel@mozilla.com>
# Date 1325114581 28800
# Node ID 5b82653ccda3937688ad204bd3c1a379daefeb01
# Parent  8e43a4f50e78f9ea19d3724e0fac313eeae967b2
add demonstration of abc error

diff -r 8e43a4f50e78 -r 5b82653ccda3 python/abstract.py
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/python/abstract.py	Wed Dec 28 15:23:01 2011 -0800
@@ -0,0 +1,38 @@
+
+def abstractmethod(method):
+    line = method.func_code.co_firstlineno
+    filename = method.func_code.co_filename
+    def not_implemented(*args, **kwargs):
+        raise NotImplementedError('Abstract method %s at File "%s", line %s should be implemented by a concrete class' % (repr(method), filename, line))
+    return not_implemented
+
+class AbstractBaseClass(object):
+
+    @abstractmethod
+    def foo(self, arg):
+        """foo does such and such"""
+
+    @abstractmethod
+    def bar(self):
+        """bar does something else"""
+
+class ConcreteClass(AbstractBaseClass):
+
+    def foo(self, arg):
+        print 'hello'
+
+if __name__ == '__main__':
+    c = ConcreteClass()
+    c.foo(1)
+    a = AbstractBaseClass()
+    try:
+        a.foo(1)
+    except NotImplementedError, e:
+        print e
+    try:
+        a.bar()
+    except NotImplementedError, e:
+        print e
+    a.foo(1)
+
+