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

[Marc via Digitalmars-d-learn]

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?

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

[Anonymouse via Digitalmars-d-learn]

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.

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

[Seb via Digitalmars-d-learn]

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