• Namespace (9/9) Sep 27 2012 What is the correct use of scope as storage class?
• Namespace (12/12) Sep 27 2012 My handy has send to soon....
• bearophile (7/17) Sep 27 2012 Generally such enforcement is not (well) implemented in the dmd
• Namespace (12/12) Sep 27 2012 So you mean this code should give an error?
• bearophile (4/16) Sep 27 2012 I think so.
• Jonathan M Davis (6/23) Sep 27 2012 Yes. You escaped a reference, which scope is supposed to prevent, but it...

"Namespace" <rswhite4 googlemail.com> writes:

What is the correct use of scope as storage class?

int counter;

void foo(scope int a) {
     counter = a;
}

void main() {
    int num = 42;
foo(num);
}

"Namespace" <rswhite4 googlemail.com> writes:

My handy has send to soon....

This code:

int counter;

void foo(scope int a) {
     counter = a;
}

void main() {
     int num = 42;
     foo(num);
}

works fine but I think it should not. So can you explain me the 
use of scope as a storage class?

"bearophile" <bearophileHUGS lycos.com> writes:

Namespace:

 int counter;

 void foo(scope int a) {
     counter = a;
 }

 void main() {
     int num = 42;
     foo(num);
 }

 works fine but I think it should not. So can you explain me the 
 use of scope as a storage class?

Generally such enforcement is not (well) implemented in the dmd 
front-end still. And I think it's mostly meant for reference 
types (class references and raw pointers), so even when it's 
implemented I think it will not give an error in your case.

Bye,
bearophile

"Namespace" <rswhite4 googlemail.com> writes:

So you mean this code should give an error?

import std.stdio;

class A { }

A ga;

void foo(scope A a) {
	ga = a;
}

void main() {
	A a = new A();
	
	foo(a);
}

"bearophile" <bearophileHUGS lycos.com> writes:

Namespace:

 So you mean this code should give an error?

 import std.stdio;

 class A { }

 A ga;

 void foo(scope A a) {
 	ga = a;
 }

 void main() {
 	A a = new A();
 	
 	foo(a);
 }

I think so.

Bye,
bearophile

"Jonathan M Davis" <jmdavisProg gmx.com> writes:

On Thursday, September 27, 2012 14:01:39 Namespace wrote:
 So you mean this code should give an error?
 
 import std.stdio;
 
 class A { }
 
 A ga;
 
 void foo(scope A a) {
 ga = a;
 }
 
 void main() {
 A a = new A();
 
 foo(a);
 }

Yes. You escaped a reference, which scope is supposed to prevent, but it 
rarely actually complains even though it's supposed to. Odds are that a lot of 
uses of scope (and in, since in is const scope) are going to break once scope 
has been fixed.

- Jonathan M Davis