[docs] [issue33477] Document that compile(code, 'exec') has different behavior in 3.7+

[Matthias Bussonnier]

Matthias Bussonnier <bussonniermatthias at gmail.com> added the comment:

Fair enough that what's new include things about Module


> The first statement in their body is not considered as a docstring anymore.

Note that this sentence read backward to me. I understand what is meant because I know the new behavior. It might be good to clarify. potentially:

> The first statement in the `body` attribute of should not be considered the docstring of the module anymore, the `docstring` attribute  is reserved for that.


Though the documentation of `compile()` does not say that `compile(...,'exec')` compile a module. It says:

> The mode argument specifies what kind of code must be compiled;
> it can be 'exec' if source consists of a sequence of statements

Which now is incorrect. I was expecting `compile(..., 'exec')` to return a Module with `None` or empty string as the docstring attribute – which is also a perfectly reasonable request.

I think that `compile`  documentation should be changed to reflect what it does. 


Or (but I see why this is un-reasonable) split add the `mode='module'` that has new behavior, while `exec` does not.

----------

_______________________________________
Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue33477>
_______________________________________