Invoking return through a function?

[Ned Batchelder]

On 10/29/17 10:18 AM, Alberto Riva wrote:
> Hello,
>
> I'm wondering if there is a way of writing a function that causes a 
> return from the function that called it. To explain with an example, 
> let's say that I want to exit my function if a dict does not contain a 
> given key. I could write:
>
> def testFun():
>   ...
>   if key not in dict:
>     return
>   ...
>
> But if this is a test I need to do a lot of times, I'd like to replace 
> it with something shorter and more explicit:
>
> def testFun():
>   ...
>   checkKey(dict, key)
>   ...
>
> and I'd like checkKey to cause a return *from testFun*. In a language 
> like Lisp this would be accomplished by defining checkKey as a macro 
> that expands into the code shown in my first example, so that the 
> return would be inside testFun and not insted checkKey. Is there a way 
> of doing something like this in Python?
>
> Another way of phrasing my question is: is there a way to cause a 
> return from a function that is higher up in the call stack, rather 
> than the currently active one, without using try/except?
>

No, there isn't.

--Ned.