[Python-ideas] Fast sum() for non-numbers

[Joshua Landau]

On 7 July 2013 03:14, Ron Adam <ron3200 at gmail.com> wrote:
>
> On 07/06/2013 04:41 PM, Joshua Landau wrote:
>>
>> On 6 July 2013 21:17, Mathias Panzenböck<grosser.meister.morti at gmx.net>
>> wrote:
>>>
>>> >After all, what does addition in the context of lists even mean?
>>
>> What it currently does.
>>
>> What is everyone so confused about?
>
>
> They aren't confused.  It just isn't a clear cut issue.
>
>
> Ideally...  And being "ideal' isn't practical in this case because it will
> need too many changes.
>
>
> Take the following example.
>
>        def add_to_values(vs, v):
>            return [n + v for n in vs]
>
> Now what do you suppose this should do?
>
> Well it it depends on what vs and v are.  It might add a value to each item
> in a list of values, it might add a value to each byte in a bytes string, it
> might concatenate a string to each string in a list,  or it might join a
> sequence to each sequence in a list.  Sounds reasonable doesn't it?
>
> Now consider that in some companies, programmers are required to take great
> care to be sure that the routines that they write can't do the wrong thing
> with lots of testing to back that up.

So why are they using a duck-typed language? It would imply that they
would never be allowed to use operators, call functions they are given
or... do anything. It seems hard to work like that.