When I do this... (compilable code)

// start of test.d //
import std.stdio;
import std.string;

class ROOT
{
	/* Members */
	public:
		BRANCH*[] Branches;
		char[] Name;

	/* Functions */
	public:
		void Add(inout BRANCH _branch)
		{
			_branch.Root = &this;
			this.Branches ~= &_branch;
		}
		void Check()
		{
			writefln("ROOT: " ~ this.Name);
			foreach(BRANCH* branch; this.Branches)
			{
				branch.Check();
			}
		}
};

class BRANCH
{
	/* Members */
	public:
		ROOT* Root;
		BRANCH*[] Branches;

	/* Functions */
	public:
		void Add(inout BRANCH _branch)
		{
			_branch.Root = this.Root;
			this.Branches ~= &_branch;
		}
		void Check()
		{
			writefln("BRANCH: " ~ this.Root.Name);
			// Access Violation happens here in 0.025
			foreach(BRANCH* branch; this.Branches)
			{
				branch.Check();
			}
		}
};

int main()
{
	ROOT root = new ROOT();
	root.Name = "test";
	BRANCH branch1 = new BRANCH();
	BRANCH branch2 = new BRANCH();

	root.Add(branch1);
	branch1.Add(branch2);
	root.Check();

	return 0;
}
// end of test.d //

It outputs this...

//////////////////
ROOT: test
BRANCH:
BRANCH:
//////////////////

In 0.025, it would give me an access violation..

I think it has to do with the "&this" not mapping to the right place. Maybe I am wrong.

Any ideas?

-- 
Thanks,
Trevor Parscal
www.trevorparscal.com
trevorparscal@hotmail.com

On Sun, 19 Jun 2005 06:54:50 -0400, Trevor Parscal <trevorparscal@hotmail.com> wrote:

> When I do this... (compilable code)
>
> // start of test.d //
> import std.stdio;
> import std.string;
>
> class ROOT
> {
> 	/* Members */
> 	public:
> 		BRANCH*[] Branches;
> 		char[] Name;
>
> 	/* Functions */
> 	public:
> 		void Add(inout BRANCH _branch)
> 		{
> 			_branch.Root = &this;
> 			this.Branches ~= &_branch;
> 		}
> 		void Check()
> 		{
> 			writefln("ROOT: " ~ this.Name);
> 			foreach(BRANCH* branch; this.Branches)
> 			{
> 				branch.Check();
> 			}
> 		}
> };
>
> class BRANCH
> {
> 	/* Members */
> 	public:
> 		ROOT* Root;
> 		BRANCH*[] Branches;
>
> 	/* Functions */
> 	public:
> 		void Add(inout BRANCH _branch)
> 		{
> 			_branch.Root = this.Root;
> 			this.Branches ~= &_branch;
> 		}
> 		void Check()
> 		{
> 			writefln("BRANCH: " ~ this.Root.Name);
> 			// Access Violation happens here in 0.025
> 			foreach(BRANCH* branch; this.Branches)
> 			{
> 				branch.Check();
> 			}
> 		}
> };
>
> int main()
> {
> 	ROOT root = new ROOT();
> 	root.Name = "test";
> 	BRANCH branch1 = new BRANCH();
> 	BRANCH branch2 = new BRANCH();
>
> 	root.Add(branch1);
> 	branch1.Add(branch2);
> 	root.Check();
>
> 	return 0;
> }
> // end of test.d //
>
> It outputs this...
>
> //////////////////
> ROOT: test
> BRANCH:
> BRANCH:
> //////////////////
>
> In 0.025, it would give me an access violation..
>
> I think it has to do with the "&this" not mapping to the right place. Maybe I am wrong.
>
> Any ideas?
>

You probably shouldn't even assume 'this' is an lvalue, but if it happens to be one, you don't even know where it's stored. I'm assuming it's just a local variable which doesn't exist after Add() returns. You seem to be assuming classes are handled like c++ classes. In D, classes only use references, which are pointers behind the scenes. So ROOT* is actually a pointer to a pointer. You should only need ROOT root; and set it to 'this' in Add() and all will be swell.

Vathix wrote:
> You probably shouldn't even assume 'this' is an lvalue, but if it happens  to be one, you don't even know where it's stored. I'm assuming it's just a  local variable which doesn't exist after Add() returns. You seem to be  assuming classes are handled like c++ classes. In D, classes only use  references, which are pointers behind the scenes. So ROOT* is actually a  pointer to a pointer. You should only need ROOT root; and set it to 'this'  in Add() and all will be swell.

Yes, good old C++ habbits die hard. Thanks for the help.

-- 
Thanks,
Trevor Parscal
www.trevorparscal.com
trevorparscal@hotmail.com