[Tutor] t = (1, *(2, 3))

[Steve Willoughby]

Lie Ryan wrote:
> Jabin Jezreel wrote:
>> I am not allowed to do
>>>>> t = (1, *(2, 3))
>>
>> But I am allowed to do
>>>>> def ts(*t):
>> ....    return t
>> ....
>>>>> ts(1, *(2, 3))
>> (1, 2, 3)
>>
>> I realize I can do
>>>>> (1,) + (2,3)
>> (1, 2, 3)
>>
>> What is the rationale behind not having t = (1, *(2, 3))
>> have the same semantics as the "ts" case above?

> I guess because it is not clear what (1, *(2, 3)) should mean.
> Parentheses when used for function call has different semantic then when
> parentheses is used for tuple syntax. Parentheses in function is part of
> the calling syntax, while parentheses in tuple is used only for grouping.

I'm not sure that's a strong argument against allowing "unfolding"
tuples in any expression beyond function calls, though, but it is how
Python works.

> PS: anyway I just realized that since tuple is immutable, having (1,
> *(2, 3)) be (1, 2, 3) would violate immutability. Maybe a list would be
> a better example.

No, it doesn't.  This would be the expression for constructing a new
tuple, which would, after that point, be immutable.