DIP23 draft: Fixing properties redux

[Zach the Mystic]

On Tuesday, 5 February 2013 at 20:24:16 UTC, Andrei Alexandrescu 
wrote:
>> I hope it at least considers my proposal with regard to 'out' 
>> return
>> values. 'out' implies ref and guarantees that the result is as 
>> good as
>> global:
>>
>> out int foo(ref int a) { return a; } // Error, 'out' return 
>> may not
>> return ref parameter
>> out int goo(ref int a) { return new int; } // Fine
>>
>> My impression was that this would solve 98% of problems, the 
>> other 2%
>> requiring scope parameters, which also imply ref:
>>
>> ref int haa(ref int a, scope int b) { return b; } // Error, 
>> may not
>> return scope parameter
>> ref int gaa(ref int a, scope int b) { return a; } // Fine
>
> I'm sorry, I didn't know of that proposal. Generally we're 
> aiming for economy of means i.e. we want to clarify semantics 
> of existing syntax instead of adding new syntax and semantics.
>
> Andrei

It's not a new syntax, just new semantics. Also, the reason for 
adding these semantics to the function signature was so that the 
compiler would never have to leave the function in order to 
compile it. It's a natural complement to ref returns' scope being 
the most local of the ref parameters, which you suggested in your 
proposal. It keeps that too.