Access to the caller's globals, not your own

[MRAB]

On 2016-11-17 05:40, Dan Sommers wrote:
> On Thu, 17 Nov 2016 16:17:51 +1100, Steven D'Aprano wrote:
>
>> ... factory functions are great. But I'm saying that as the writer of
>> the library, not the user of the library. Can you imagine expecting
>> users to do this?
>
>> from math import trig
>> sin = trig.build('sine')
>> result = sin(0.1)
>
> No, but I could expect users to do this:
>
>     import math # trig functions take radians by default
>     math = math.degree_math # but I like degrees
>
> Or to choose from one of these:
>
>     import math # trig functions take radians by default
>     import math.degree_math as math # but I like degrees
>
> Or to choose from one of these:
>
>     import math.radian_math as math # use the radians version
>     import math.degree_math as math # use the degrees version
>
> The complexity is taken on once, by the library author, who (presumably)
> understands the complexity better than the users do.
>
[snip]
I wonder if it would be possible to make modules callable. You would do 
this by adding a __call__ function, and this function could be a factory 
function:

     import math
     degree_math = math('degree')

This would be equivalent to:

     import math
     degree_math = math.__call__('degree')

Also, a possible syntax extension:

     import math('degree') as degree_math

This would be equivalent to:

     import math as __temp__
     degree_math = __temp__.__call__('degree')
     del __temp__

If you wrote:

     import math('degree')

this would be equivalent to:

     import math as __temp__
     math = __temp__.__call__('degree')
     del __temp__