Hello Payal!
On Saturday June 26 2010 19:05:16 Payal wrote:
> Can we say that our own exception classes have only maybe a doc-string
> and pass, nothing more?
No, you let the exception transport the information that you need for handling
the error. This is an exception that I use to transport user visible error
messages in a compiler, that I write as a hobby:
class UserException(Exception):
'''Exception that transports user visible error messages.'''
def __init__(self, message, loc=None, errno=None):
Exception.__init__(self)
self.msg = message
self.loc = loc
self.errno = errno
def __str__(self):
if self.errno is None:
num_str = ''
else:
num_str = '(#%s) ' % str(self.errno)
return 'Error! ' + num_str + self.msg + '\n' + str(self.loc) + '\n'
def __repr__(self):
return self.__class__.__name__ + str((self.msg, self.loc,
self.errno))
It contains:
self.msg : The error message
self.loc : An object encoding the location of the error in the program's
text. Together with the file name and the text.
self.errno : An integer to identify the error, for the test framework.
That said; the expression's type and the error message are often sufficient to
handle the error.
Eike.
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