It's possible to declare a variable inside a static foreach()?

[Seb]

On Thursday, 21 December 2017 at 16:38:36 UTC, Anonymouse wrote:
> On Thursday, 21 December 2017 at 16:25:00 UTC, Marc wrote:
>> For example, I'd like to declare a variable inside a static 
>> foreach like in below code, just for better organization, 
>> otherwise, I have to use the value directly instead of the 
>> variable. If the value is used more than once, it might be 
>> inviable.
>>
>>>	enum allMembers = __traits(derivedMembers, C);
>>>	static foreach(enum string member; allMembers) {		
>>>		enum attributes = __traits(getAttributes, 
>>>__traits(getMember, C, member));
>>>		static foreach(C c; attributes) {
>>>			writeln(c);
>>>		}
>>>	}
>>
>> I got redefinition erros of "atributes" on this. Can I have 
>> this only at compile time?
>
> I don't think you need static for foreach of __traits 
> allMembers/derivedMembers and .tupleof. It unrolls at 
> compile-time and builds fine for me if I just remove the 
> statics. https://run.dlang.io/is/Ln3kVZ
>
>> /*static*/ foreach(C c; attributes)
> Mind that c will not be of type C but of the type of the 
> attribute.


The trick with static foreach is to create a new scope:

https://run.dlang.io/is/wODA0x

DIP1010 [1] suggested __local but while this is implemented, it 
it's not exposed yet.
There's also a bit of discussion about this at [2].

[1] 
https://github.com/dlang/DIPs/blob/master/DIPs/DIP1010.md#local-declarations
[2] https://github.com/dlang/phobos/pull/5729