Lazy eval

[Walter Bright]

BCS wrote:
> Thinking of it that way, changing the API from one to the other is 
> *never* safe. This means that using a T delegate() as a parameter might 
> as well be considered an unsafe practice. If you started with just T, 
> your locked in for all time. Starting with T delegate() is almost as bad.
> 
> Having a feature that is nearly impossible to use safely may well be 
> worse than not having the feature.

Changing the API is always problematic, including with traditional 
features like implicit conversions, inout, etc. As I posted before, the 
pragmatic way to change an API is to create a new name with the new 
interface, and deprecate the old one. This is not a problem that is new 
or unique to delegate conversions. It's as old as programming.

As for delegate conversions being nearly impossible to use safely, I 
don't understand that at all. I would agree that it is a probably unique 
feature for C like languages, and hence people will perhaps make 
mistakes with it until it becomes familiar, expected, and passe.