[Python-ideas] PEP proposal: unifying function/method classes

[Antoine Pitrou]

On Fri, 23 Mar 2018 07:25:33 +0100
Jeroen Demeyer <J.Demeyer at UGent.be> wrote:

> On 2018-03-23 00:36, Antoine Pitrou wrote:
> > It does make sense, since the proposal sounds ambitious (and perhaps
> > impossible without breaking compatibility).  
> 
> Well, *some* breakage of backwards compatibility will be unavoidable.
> 
> 
> My plan (just a plan for now!) is to preserve backwards compatibility in 
> the following ways:
> 
> * Existing Python attributes of functions/methods should continue to 
> exist and behave the same
> 
> * The inspect module should give the same results as now (by changing 
> the implementation of some of the functions in inspect to match the new 
> classes)
> 
> * Everything from the documented Python/C API.
> 
> 
> This means that I might break compatibility in the following ways:
> 
> * Changing the classes of functions/methods (this is the whole point of 
> this PEP). So anything involving isinstance() checks might break.
> 
> * The undocumented parts of the Python/C API, in particular the C structure.

One breaking change would be to add __get__ to C functions.  This means
e.g. the following:

class MyClass:
    my_open = open

would make my_open a MyClass method, therefore you would need to spell
it:

class MyClass:
    my_open = staticmethod(open)

... if you wanted MyClass().my_open('some file') to continue to work.

Of course that might be considered a minor annoyance.

Regards

Antoine.