[Grace-core] Minutes of Teleconference 2011.11.30

[Andrew P. Black]

On 30 Nov 2011, at 17:28 , James Noble wrote:

> And then:
> * Andrew's solution in dynamic world - that somehow applies at only lower language levels
>      dynamic checks on assignment & parameter passing  
>       that prevent assigning "none" to a variable, or passing "none" down as a method argument.
>       return values are *not* restricted...
> 
> * Kim's solution in the static world - if you could have a *none*, you'll need to mention that in the types
>      (one way or another)
> 
> what Scala does - http://blog.sanaulla.info/2009/07/12/nothingness/
>  (5 different null-like things)
> 
> what Python does - http://boodebr.org/main/python/tourist/none-empty-nothing
>  (3 different null-like things :-)


There is another case where we should issue a warning for novices: when a method might return None and it might return a value, depending on control flow.  This should always be wrong, I think.

	Andrew