More exceptions experiments

test/tests/exceptions.py

@@ -10,3 +10,32 @@ def throw(x):
 # Both print "Exception"
 throw(Exception)
 throw(Exception())
+
+def catches(t, e):
+    try:
+        raise e
+    except t:
+        return True
+    except:
+        return False
+
+print catches(Exception, Exception)
+print catches(Exception, Exception())
+print catches(Exception(), Exception())
+print catches(Exception, StopIteration())
+print catches(Exception, RuntimeError())
+print catches(Exception, KeyboardInterrupt())
+print catches(None, Exception())
+print catches(1, Exception())
+
+_StopIteration = StopIteration
+def f1():
+    import __builtin__
+    __builtin__.StopIteration = StopIteration = 0
+
+    # This should still work:
+    for i in xrange(5):
+        print i
+
+    __builtin__.StopIteration = _StopIteration
+f1()

test/tests/exceptions_nested.py

@@ -81,6 +81,7 @@ def f2_2():
             print n, sys.exc_info()[0].__name__
 
         print "done", n, sys.exc_info()[0].__name__
+    print "after", n, sys.exc_info()[0].__name__
 f2_2()
 
 def f3():
@@ -109,3 +110,51 @@ def f3():
     finally:
         print "outer finally"
 f3()
+
+def f4():
+    print
+    print "f4"
+
+    # This test answers the question of what the exact behavior of the "raise" (no argument) statement is,
+    # especially after a sub-exception has changed sys.exc_info
+
+    try:
+        try:
+            raise AttributeError()
+        except AttributeError:
+            try:
+                raise NotImplementedError()
+            except:
+                pass
+
+            # Even though lexically it looks like we're handling an AttributeError,
+            # at this point the "most recent exception" is a NotImplementedError,
+            # so when we "raise" we should throw that.
+            raise
+    except AttributeError:
+        print "caught attribute error (makes sense, but wrong)"
+    except NotImplementedError:
+        print "caught not implemented error (weird, but right)"
+f4()
+
+def f5():
+    print
+    print "f5"
+
+    # Based on what I learned from f4, I guess you can put a "raise" outside a try-catch block:
+
+    def inner():
+        try:
+            raise AttributeError()
+        except:
+            pass
+
+        print "reraising"
+        raise
+
+    try:
+        inner()
+        assert 0, "shouldn't get here"
+    except AttributeError:
+        print sys.exc_info()[0].__name__
+f5()