Ben Finney <[EMAIL PROTECTED]> wrote:
> I want my modules to (sometimes) define an abstract base exception
> class, that all other exceptions in that module inherit from.
[re-posting with the implementation properly foo-ified]
Not a whole lot of feedback on this, so here's the implementation I
decided upon.
class FooException(Exception):
""" Base class for all exceptions in this module """
def __init__(self):
if self.__class__ is FooException:
raise NotImplementedError, \
"%s is an abstract class for subclassing" % self.__class__
class FooBarTypeError(TypeError, FooException):
""" Raised when the foo gets a bad bar """
class FooDontDoThatError(AssertionError, FooException):
""" Raised when the foo is asked to do the wrong thing """
This allows the exceptions for the module to behave similarly to their
leftmost base exception; but because they all inherit from the
abstract base class exception for the module, it also allows for this
idiom:
import foo
try:
foo.do_stuff(bar)
except FooException, e:
special_error_handler(e)
Any more comment on this technique? Any other significant use cases
for abstract base classes?
--
\ "For man, as for flower and beast and bird, the supreme triumph |
`\ is to be most vividly, most perfectly alive" -- D.H. Lawrence. |
_o__) |
Ben Finney
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