[Python-ideas] Reverse assignment operators (=+, =-, =*, =/, =//, =**, =%)

[Mikhail V]

On 14 November 2016 at 00:08, Todd <toddrjen at gmail.com> wrote:
>
> On Sun, Nov 13, 2016 at 4:00 PM, Mikhail V <mikhailwas at gmail.com> wrote:
>>
>> On 12 November 2016 at 21:08, João Matos <jcrmatos at gmail.com> wrote:
>>
>> > What I would like to propose is the creation of the reverse:
>> > a =+ c is the same as a = c + a
>> > a =- c is the same as a = c - a
>> > a =* c is the same as a = c * a
>> > a =/ c is the same as a = c / a
>> > a =// c is the same as a = c // a
>> > a =% c is the same as a = c % a
>> > a =** c is the same as a = c ** a
>>
>> A good syntax example:
>>
>> a = sum (a, c)
>> a = mul (a, c)
>> a = div (a, c)
>
>
> Except that there is no "div" in python 3.x, and "sum(a, c)" does not add
> "a" and "c".
>
>>
>> Another good syntax, I'm not a fan of, but at least intuitive and
>> learnt in school:
>>
>> a = a + c
>> a = a * c
>> a = a / c
>
>
> How is using a function better than using an operator?  Especially
> considering the ambiguity issues you just demonstrated.
>
> The fact the operator version is part of the core language while the
> function versions aren't even builtins (they are in the "operator" module)
> suggests to me that the function version is not the preferred version in
> Python.
>
>>
>> Bad syntax, not readable:
>>
>> a += c
>> a -= c
>> a *= c
>>
>
> What, specifically, is not readable about this syntax?
>
>>
>> As for me, I would even prohibit all these +=  for the sake of
>> readability.
>
>
> Great, so I will have to make a copy of my 500 MB array every time I want to
> do a simple mathematical operation on it rather than being able to do the
> operation in-place.


It is kind of clear from the context, that I am speaking of syntax and
not how things
are working under the hood, or?
If a compiler cannot optimize "a = a + 1" into an in-place operation,
that is misfortune.

In numpy one can define in-place calulations, if I am not mistaken,
with np.vectorize.

A better option would be to support unary operators so the user
can write directly without assignment:

inc (a, 1)

Would mean in-place increment "a" with 1


>> a += c
>> a -= c
>> a *= c
>>
>
> What, specifically, is not readable about this syntax?

Well, if you find this syntax readable, then I am afraid we are on the opposite
sides of barricades ;)

Mikhail