added classes as exceptions

Doc/ref/ref6.tex

@@ -324,13 +324,20 @@ raise_stmt:     "raise" condition ["," condition]
 \end{verbatim}
 
 \verb@raise@ evaluates its first condition, which must yield
-a string object.  If there is a second condition, this is evaluated,
-else \verb@None@ is substituted.
+a string, class, or instance object.  If there is a second condition,
+this is evaluated, else \verb@None@ is substituted.  If the first
+condition is a class object, then the second condition must be an
+instance of that class or one of its derivatives.  If the first
+condition is an instance object, the second condition must be
+\verb@None@.
 \index{exception}
 \indexii{raising}{exception}
 
-It then raises the exception identified by the first object,
-with the second one (or \verb@None@) as its parameter.
+If the first object is a class or string, it then raises the exception
+identified by the first object, with the second one (or \verb@None@)
+as its parameter.  If the first object is an instance, it raises the
+exception identified by the class of the object, with the instance as
+its parameter.
 
 \section{The {\tt break} statement}
 \stindex{break}

Doc/ref/ref7.tex

@@ -201,10 +201,11 @@ clause, if present, must be last; it matches any exception.  For an
 except clause with a condition, that condition is evaluated, and the
 clause matches the exception if the resulting object is ``compatible''
 with the exception.  An object is compatible with an exception if it
-is either the object that identifies the exception or it is a tuple
-containing an item that is compatible with the exception.  Note that
-the object identities must match, i.e. it must be the same object, not
-just an object with the same value.
+is either the object that identifies the exception, or (for exceptions
+that are classes) it is a base class of the exception, or it is a
+tuple containing an item that is compatible with the exception.  Note
+that the object identities must match, i.e. it must be the same
+object, not just an object with the same value.
 \kwindex{except}
 
 If no except clause matches the exception, the search for an exception

Doc/ref6.tex

@@ -324,13 +324,20 @@ raise_stmt:     "raise" condition ["," condition]
 \end{verbatim}
 
 \verb@raise@ evaluates its first condition, which must yield
-a string object.  If there is a second condition, this is evaluated,
-else \verb@None@ is substituted.
+a string, class, or instance object.  If there is a second condition,
+this is evaluated, else \verb@None@ is substituted.  If the first
+condition is a class object, then the second condition must be an
+instance of that class or one of its derivatives.  If the first
+condition is an instance object, the second condition must be
+\verb@None@.
 \index{exception}
 \indexii{raising}{exception}
 
-It then raises the exception identified by the first object,
-with the second one (or \verb@None@) as its parameter.
+If the first object is a class or string, it then raises the exception
+identified by the first object, with the second one (or \verb@None@)
+as its parameter.  If the first object is an instance, it raises the
+exception identified by the class of the object, with the instance as
+its parameter.
 
 \section{The {\tt break} statement}
 \stindex{break}

Doc/ref7.tex

@@ -201,10 +201,11 @@ clause, if present, must be last; it matches any exception.  For an
 except clause with a condition, that condition is evaluated, and the
 clause matches the exception if the resulting object is ``compatible''
 with the exception.  An object is compatible with an exception if it
-is either the object that identifies the exception or it is a tuple
-containing an item that is compatible with the exception.  Note that
-the object identities must match, i.e. it must be the same object, not
-just an object with the same value.
+is either the object that identifies the exception, or (for exceptions
+that are classes) it is a base class of the exception, or it is a
+tuple containing an item that is compatible with the exception.  Note
+that the object identities must match, i.e. it must be the same
+object, not just an object with the same value.
 \kwindex{except}
 
 If no except clause matches the exception, the search for an exception