[Python-Dev] PEP-317

[Tim Peters]

[Terence Way]
> There is a rather pleasing symmetry between
>      raise SomeClass, arg
> and
>      assert expr, arg
>
> Is this intentional?  If so, should the assert form be deprecated as
> well?

The symmetry is purely syntactic, and is misleading:  assert is a control
structure, and doesn't evaluate "arg" unless the runtime value of expr is
false.  For example,

>>> assert True, 1/0
>>> assert False, 1/0
Traceback (most recent call last):
  File "<stdin>", line 1, in ?
ZeroDivisionError: integer division or modulo by zero
>>>

raise always evaluates its arg.