How to validate the __init__ parameters

[Steven D'Aprano]

On Tue, 22 Dec 2009 00:18:21 +0000, r0g wrote:

> Yikes, glad to be set me straight on that one! Thanks :) It's a pity
> though, I really like the way it reads. Is there anything similar with
> ISN'T disabled when optimizations are turned on?

Yes: an explicit test-and-raise.

if not condition: 
    raise Exception



> I guess I could do the following but it seems a bit ugly in comparison
> :(
> 
> if len(foo) <= 5: raise Exception

Write a helper function:

def fail_unless(condition, exception=Exception, msg=""):
    if not condition:
        raise exception(msg)


fail_unless(len(foo) <= 5, ValueError, 'string too long')



-- 
Steven