Syntax for one-line "nonymous" functions in "declaration style"

[Alexey Muranov]

On jeu., mars 28, 2019 at 5:00 PM, python-list-request at python.org wrote:
> On 2019-03-27 10:42 a.m., Paul Moore wrote:
>>  On Wed, 27 Mar 2019 at 12:27, Alexey Muranov 
>> <alexey.muranov at gmail.com> wrote:
>>>  On mer., mars 27, 2019 at 10:10 AM, Paul Moore 
>>> <p.f.moore at gmail.com>
>>>  wrote:
>>>>  On Wed, 27 Mar 2019 at 08:25, Alexey Muranov
>>>>  <alexey.muranov at gmail.com> wrote:
>>>>>   Whey you need a simple function in Python, there is a choice
>>>>>  between a
>>>>>   normal function declaration and an assignment of a anonymous
>>>>>  function
>>>>>   (defined by a lambda-expression) to a variable:
>>>>> 
>>>>>       def f(x): return x*x
>>>>> 
>>>>>   or
>>>>> 
>>>>>       f = lambda x: x*x
>>>>> 
>>>>>   It would be however more convenient to be able to write instead 
>>>>> just
>>>>> 
>>>>>       f(x) = x*x
>>>>  Why? Is saving a few characters really that helpful? So much so 
>>>> that
>>>>  it's worth adding a *third* method of defining functions, which 
>>>> would
>>>>  need documenting, adding to training materials, etc, etc?
>>>  Because i think i would prefer to write it this way.
>>  That's not likely to be sufficient reason for changing a language
>>  that's used by literally millions of people.
>> 
>>>  (Almost no new documentation or tutorials would be needed IMHO.)
>>  Documentation would be needed to explain how the new construct 
>> worked,
>>  for people who either wanted to use it or encountered it in other
>>  people's code. While it may be obvious to you how it works, it 
>> likely
>>  won't be to others, and there will probably be edge cases you 
>> haven't
>>  considered that others will find and ask about.
> 
> For what it's worth, if I encountered "f(x) = x * x" in code, my first
> thought would be that Python somehow added a way to return an 
> assignable
> reference from a function, rather than this being an anonymous 
> function
> declaration.
> 
> So documentation of that syntax would 100% be required
> 
> Alex
> 

The thing to the right of the assignment symbol represents a value (an 
object), but the thing to the left does not represent a value, it 
represents a place for a value.

What would an "assignable reference" mean? Say, variable "x" holds an 
"assignable reference", what can be done next?

Alexey.