[Python-Dev] ',' precedence in documentation (original) (raw)

Michele Simionato michele.simionato at gmail.com
Mon Sep 29 16:12:13 CEST 2008

I like Martin's proposals (use a function, remove -O) very much. Actually I wanted to propose the same months ago. Here is my take at the assert function, which I would like to be able to raise even exceptions different from AssertionError:

def assert_(cond, exc, *args): """Raise an exception if cond is not satisfied. exc can be a template string (then args are the interpolation arguments) or an exception class (then args are passed to the constructor). Here are a few examples:

>>> assert_(False, 'ahia!')
Traceback (most recent call last):
   ...
AssertionError: ahia!

>>> assert_(False, ValueError)
Traceback (most recent call last):
  ...
ValueError

>>> a = 1
>>> assert_(isinstance(a, str), TypeError, '%r is not a string' % a)
Traceback (most recent call last):
TypeError: 1 is not a string

"""
if isinstance(exc, basestring):
    raise AssertionError(exc % args)
elif inspect.isclass(exc) and issubclass(exc, Exception):
    raise exc(*args)
else:
    raise TypeError('The second argument of assert_ must be a string '
    'or an exception class, not %r' % exc)

M. Simionato

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