null [re: spec#]

[Simen kjaeraas]

steveh <steveh57 at useshotmai.l> wrote:

> I've known there are hidden tradeoffs when using these 'intelligent'  
> types. Non-null types add terrible runtime checks everywhere. It's  
> simply not acceptable in a systems programming language. Operating  
> system kernel uses very efficient uninitialized arrays for buffers. It's  
> crazy to force this non-null hype down our throats.

And here you are sorely mistaken. The point of non-nullable types is the
exact opposite. In fact, the only time you need a runtime check is when
converting a nullable type to a non-nullable - after that, it's guaranteed
not to be null. When in addition there is no way to create a non-nullable
variable without initializing it (and possibly checking that the
initializing value is not null, if it comes from a nullable source),
the result is a great decrease in runtime checks, not an increase.


-- 
Simen