On 9/19/05, Terry Reedy <[EMAIL PROTECTED]> wrote: > > I consider the current situation to be a consistency feature. To a first > approximation, Python function calls 'pass' objects by name-binding: > > param_name_list = arg_object_list > > Disabling structure unpacking in this assignment would make the language > slightly more complex. Someone else posted the same observation in c.l.p.
Maybe, but there are enough differences between parameter/argument lists and sequences that this consistency sounds rather foolish to me. In fact, the feature came from a similar feature in ABC, but in ABC, parameter lists *were* considered assignment targets -- the outer level of parentheses was just a special case of tuple unpacking. Not so in Python, which has keyword parameters, *varargs, **keywords, and where f(x,) is the same as f(x) -- even though (x,) is a tuple and (x) is not. Also, I bet many people will be surprised to know that this code doesn't work: add = lambda (x, y): x+y print add(1, 2) > Another thought. By directly unpacking and not naming a sequence, one > 'announces' that only the components are of interest and that nothing will > be done with the sequence object itself. Fair enough, though I'm not sure what use we can make of that information. -- --Guido van Rossum (home page: http://www.python.org/~guido/) _______________________________________________ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
