[Tutor] Dynamically changing a class

[Kent Johnson]

Ricardo Aráoz wrote:

> Yep. And once you've got it pls explain it too me, too lazy today to
> pick the manual. :)

I included a link to my explanation previously. I'm too lazy to try to 
do better.

> Any easier way?

Easier how? I don't know what could be easier to implement than a single 
function call. What did you have in mind? These are all equivalent, take 
your pick:

myObj.mfunc = newfunc.__get__(myObj, MyClass)
myObj.mfunc = types.MethodType(newfunc, myObj, MyClass)
myObj.mfunc = new.instancemethod(newfunc, myObj, MyClass)

For my own interest I looked into how these are actually implemented 
with an eye to which one might be preferred.

new.instancemethod has the advantage of being documented in the library 
reference but the source says it is deprecated and it is a synonym for 
types.MethodType (in new.py).

types.MethodType is defined in types.py as
   MethodType = type(_x._m)
where _x is a class and _m is a method; i.e. types.MethodType is 
literally 'the type of a bound method'. It is fairly explicit at the 
point of use - 'give me a method'.

newfunc.__get__ is defined by func_descr_get() in Objects/funcobject.c. 
It delegates to PyMethod_New() so it is essentially calling MethodType. 
It's a bit obscure at the point of use.

So I guess I prefer MethodType(newfunc, myObj, MyClass)

Kent