Hi,

Python 2.3.3 (#1, Feb 5 2005, 16:22:10) [GCC 3.3.3 (SuSE Linux)] on linux2[color=blue][color=green][color=darkred]
>>> assert 0, "foo"[/color][/color][/color]
Traceback (most recent call last):
File "<stdin>", line 1, in ?
AssertionError: foo[color=blue][color=green][color=darkred]
>>> assert(0, "foo")
>>>[/color][/color][/color]

If you use parenthesis for the assert statement, it never
raises an exception.

Up to now I raised strings, but since this is deprecated,
I switched to use the second argument for the assert
statement.

Is it possible to change future python versions, that
assert accept parenthesis?

Thomas

--
Thomas Güttler, http://www.thomas-guettler.de/

> "Thomas Guettler" <guettli@thomas-guettler.de> wrote in message[color=blue]
> news:pan.2005.02.23.09.57.43.578480@thomas-guettler.de...
> Hi,[/color]
[color=blue]
> Python 2.3.3 (#1, Feb 5 2005, 16:22:10) [GCC 3.3.3 (SuSE Linux)] on[/color]
linux2[color=blue][color=green][color=darkred]
> >>> assert 0, "foo"[/color][/color][/color]

Assert that 0 is true. If that fails, raise AssertionError("foo").
[color=blue]
> Traceback (most recent call last):
> File "<stdin>", line 1, in ?
> AssertionError: foo[color=green][color=darkred]
> >>> assert(0, "foo")[/color][/color][/color]

Assert that the tuple (0, "foo") is true. Non-empty tuples are always true.
[color=blue][color=green][color=darkred]
> >>>[/color][/color]
>
> If you use parenthesis for the assert statement, it never
> raises an exception.[/color]
[color=blue]
> Up to now I raised strings, but since this is deprecated,
> I switched to use the second argument for the assert
> statement.[/color]
[color=blue]
> Is it possible to change future python versions, that
> assert accept parenthesis?[/color]

As shown above, it does, but it doesn't do quite what you expected. For
further enlightenment, try the following and think through why each one
gives the results it does:

assert (), 'spam'
assert [], 'eggs'
assert {}, 'spam and eggs'
assert (0,), 'spam, spam, and eggs'
assert (0, "foo"), 'spam, spam, eggs, and spam'
assert 0, "foo", 'shrubbery'

The last will give a syntax error. Can you spot why?
[color=blue]
> Thomas[/color]
[color=blue]
> --
> Thomas Güttler, http://www.thomas-guettler.de/[/color]

Thomas Guettler wrote:[color=blue]
> Hi,
>
> Python 2.3.3 (#1, Feb 5 2005, 16:22:10) [GCC 3.3.3 (SuSE Linux)] on linux2
>[color=green][color=darkred]
>>>>assert 0, "foo"[/color][/color]
>
> Traceback (most recent call last):
> File "<stdin>", line 1, in ?
> AssertionError: foo
>[color=green][color=darkred]
>>>>assert(0, "foo")
>>>>[/color][/color]
>
>
> If you use parenthesis for the assert statement, it never
> raises an exception.
>
> Up to now I raised strings, but since this is deprecated,
> I switched to use the second argument for the assert
> statement.
>
> Is it possible to change future python versions, that
> assert accept parenthesis?[/color]
You are confusing assert with raise.

assert test, text

behaves like:

if __debug__ and test:
raise AssertionError, text

As far as raise goes, where you have been writing:

raise "some complaint"

you could simply use:

raise ValueError, "some complaint"

or:

raise ValueError("some complaint")

--Scott David Daniels
Scott.Daniels@Acm.Org

Thomas Guettler wrote:[color=blue]
> Is it possible to change future python versions, that
> assert accept parenthesis?[/color]


It's possible, but extremely unlikely that it will ever happen. assert
is not a function, but a statement (like print). Statements don't use
parentheses; when you use parentheses, it considers that a tuple.

For example, if you try this with print:

print ("hello","world")

you see that in prints out a tuple value, rather than treating "hello"
and "world" as arguments. Same thing with assert.


--
CARL BANKS