Code:
----
const { /// [1]
	int a = 3;
}

void main()
{
	const { /// [2]
		int b = 4;
	}
}
----

Why is [1] allowed, but not [2]?

Namespace:

> Code:
> ----
> const { /// [1]
> 	int a = 3;
> }
>
> void main()
> {
> 	const { /// [2]
> 		int b = 4;
> 	}
> }
> ----
>
> Why is [1] allowed, but not [2]?

Think about what this does:

void main() {
    {
        int b = 4;
    }
}


It creates a new scope inside the function. How do you tell apart the syntax to create a new scope from having a "group tagging" as in the global case?

Bye,
bearophile

On Wednesday, 18 September 2013 at 13:42:37 UTC, bearophile wrote:
> Namespace:
>
>> Code:
>> ----
>> const { /// [1]
>> 	int a = 3;
>> }
>>
>> void main()
>> {
>> 	const { /// [2]
>> 		int b = 4;
>> 	}
>> }
>> ----
>>
>> Why is [1] allowed, but not [2]?
>
> Think about what this does:
>
> void main() {
>     {
>         int b = 4;
>     }
> }
>
>
> It creates a new scope inside the function. How do you tell apart the syntax to create a new scope from having a "group tagging" as in the global case?
>
> Bye,
> bearophile

If a type modifier is in front of '{' it's a group tagging, otherwise a scope.

Same thing with debug:

{
    // scope code
}

debug {
    // debug code
}

On Wednesday, 18 September 2013 at 13:23:10 UTC, Namespace wrote:
> Code:
> ----
> const { /// [1]
> 	int a = 3;
> }
>
> void main()
> {
> 	const { /// [2]
> 		int b = 4;
> 	}
> }
> ----
>
> Why is [1] allowed, but not [2]?

Citing grammar:

FunctionBody:
    BlockStatement
    BodyStatement
    InStatement BodyStatement
    OutStatement BodyStatement
    InStatement OutStatement BodyStatement
    OutStatement InStatement BodyStatement

BlockStatement:
    { }
    { StatementList }

As you can see there is no room for attributes. Why dmd does not support attributes here is separate question - probably because such construct would be confused with lambda, but this is not a serious reason.

On Wednesday, 18 September 2013 at 14:17:04 UTC, Maxim Fomin wrote:
> On Wednesday, 18 September 2013 at 13:23:10 UTC, Namespace wrote:
>> Code:
>> ----
>> const { /// [1]
>> 	int a = 3;
>> }
>>
>> void main()
>> {
>> 	const { /// [2]
>> 		int b = 4;
>> 	}
>> }
>> ----
>>
>> Why is [1] allowed, but not [2]?
>
> Citing grammar:
>
> FunctionBody:
>     BlockStatement
>     BodyStatement
>     InStatement BodyStatement
>     OutStatement BodyStatement
>     InStatement OutStatement BodyStatement
>     OutStatement InStatement BodyStatement
>
> BlockStatement:
>     { }
>     { StatementList }
>
> As you can see there is no room for attributes. Why dmd does not support attributes here is separate question - probably because such construct would be confused with lambda, but this is not a serious reason.

Should I open an enhancement report?

On Wednesday, 18 September 2013 at 14:23:25 UTC, Namespace wrote:
>
> Should I open an enhancement report?

Of course you are always free to open enhancement reports.