Hi,

Wouldn't the compiler be smart with this shadowing variable, example:

void main(){
    int j;
    for(int i=0,j=0;i<10;++i){}
    return;
}

onlineapp.d(3): Error: variable `j` is shadowing variable `onlineapp.main.j`

So in the "for loop" shouldn't "i" be declared and "j" just be assigned to 0?

I mean this is a bit weird, imagine I have different "for loops" and in this situation I'll need to do this:

j=0;
for(int i=0;i<10;++i){}

Otherwise:

for(i=0,j=0;i<10;++i){}

This works, but now "i" variable will be out of the "for loop" scope.

Matheus.

On Friday, 10 December 2021 at 13:35:37 UTC, Matheus wrote:
> Hi,
>
> Wouldn't the compiler be smart with this shadowing variable, example:
>
> void main(){
>     int j;
>     for(int i=0,j=0;i<10;++i){}
>     return;
> }
>
> onlineapp.d(3): Error: variable `j` is shadowing variable `onlineapp.main.j`
>
> So in the "for loop" shouldn't "i" be declared and "j" just be assigned to 0?

Intuitively, there are two possible interpretations here for inexperienced humans (and you seem to be favoring the latter):
   1. declare a new "j" variable to be visible only inside of the loop.
   2. reuse the existing "j" variable.

But only one of them is a correct description of what actually happens when the compiler processes this code. So it's a good thing that the compiler is smart enough to reject ambiguous code and prevent humans from making mistakes.

On Friday, 10 December 2021 at 21:55:17 UTC, Siarhei Siamashka wrote:
> ...
>    2. reuse the existing "j" variable.

Yes.

> But only one of them is a correct description of what actually happens when the compiler processes this code. So it's a good thing that the compiler is smart enough to reject ambiguous code and prevent humans from making mistakes.

Hmm I see your point. And I just thought in cases like this the reuse should be the way, but I can see that this is a small snippet and in a big code this may hurt someone.

Matheus.

On Saturday, 11 December 2021 at 01:02:36 UTC, frame wrote:
> ...
> You probably want this:
>
> ```d
> int j;
> for({int i=0; j=0;} i<10; ++i){}
> ```
>
> Beware, this syntax comes directly from hell

Well this works! :)

I'm just a bit intrigued by your last sentence. Is there anything evil this may result or anything that I should be aware of?

Matheus.