[Python-ideas] A "local" pseudo-function

[Soni L.]

On 2018-04-29 10:20 PM, Ethan Furman wrote:
> On 04/29/2018 01:20 PM, Tim Peters wrote:
>
>> So, e.g.,
>>
>> """
>> a = 42
>>
>> def showa():
>>      print(a)
>>
>> def run():
>>      global a
>>
>>      local a: # assuming this existed
>>          a = 43
>>          showa()
>>      showa()
>> """
>>
>> would print 43 and then 42.  Which makes "local a:" sound senseless on
>> the face of it ;-)  "shadow" would be a more descriptive name for what
>> it actually does.
>
> Yeah, "shadow" would be a better name than "local", considering that 
> it effectively temporarily changes what other functions see as 
> global.  Talk about a debugging nightmare!  ;)

That ain't shadow. That is dynamic scoping.

Shadowing is something different:

def f():
     a = 42
     def g():
         print(a)
     local a:
         a = 43
         g()
     g()

should print "42" both times, *if it's lexically scoped*.

If it's lexically scoped, this is just adding another scope: blocks. 
(instead of the smallest possible scope being function scope)

>
> -- 
> ~Ethan~
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