2010/1/9 cool-RR <cool-rr@cool-rr.com>

I propose that when raising an exception without providing a message, the first line of the docstring will be shown. (I mean shown in the traceback where the message would normally be.

Example session:

####################################

>>> class MyExcpetion(Exception):
'''Trying to fit a square piece into a round hole.'''

class MyException(Exception):
     "Some docstring"
    def __init__(self, msg=None):
         if msg == None:
             msg = self.__doc__
         Exception.__init__(self, msg)

All the best,

Michael

>>> raise MyExcpetion('Problem bla bla')

Traceback (most recent call last):
  File "<pyshell#3>", line 1, in <module>

   raise MyExcpetion('Problem bla bla')
MyExcpetion: Problem bla bla

>>> raise MyExcpetion()

Traceback (most recent call last):

  File "<pyshell#4>", line 1, in <module>
   raise MyExcpetion()
MyExcpetion: Trying to fit a square piece into a round hole.

####################################

This will be useful for me because I often raise exceptions and have nothing to say besides repeating the exception's docstring, and I have many places in the code where I'd want to conditionally raise it. I'm faced with two choices: Type the exception's docstring in every place, which is lame, and breaks DRY. Or just raise the exception without any message, which may potentially confuse users.

This is the motivation for this suggestion, so I could be succinct without confusing users.

What do you think?

Ram.

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