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digitalmars.D.learn - porperty problem..

reply BLS <windevguy hotmail.de> writes:
Hi I have a forward reference pb in conjunction with  property.
Err msg is :
forward refrence to inferred return type of function call s1.servername.
any ideas ? beside, where are the  property docs ?
thanks, bjoern

final class LoadBalancer {
	private static LoadBalancer lb;
	private Server[] servers;
	
	static this() {
		synchronized lb = new LoadBalancer;
	}
	
	private this() {
		Server s1 = new Server();
		s1.servername = "Server 1";  // ERROR
		servers ~= s1;
	}
	
	public static LoadBalancer getLoadBalancer() {
       return lb;
     }

	 property nextServer() {
		return servers[0];
	}
		
	class Server {
		private string _name, _id;
		
		 property servername(string name) {
			_name = name;
		}
		 property servername() {
			return _name;
		}
	}
}
Jun 28 2010
next sibling parent "Simen kjaeraas" <simen.kjaras gmail.com> writes:
  BLS <windevguy hotmail.de> wrote:


 Hi I have a forward reference pb in conjunction with  property.
 Err msg is :
 forward refrence to inferred return type of function call s1.servername.
 any ideas ?



No line number? If so, file it in bugzilla. You might also want to file
a bug for the forward reference problems.



  beside, where are the  property docs ?



No idea.


This:

 	 property nextServer() {
 		return servers[0];
 	}



I believe  property does not cause type inference.


=>  property void servername(string name)

 		 property servername(string name) {
 			_name = name;
 		}




=>  property string servername()

 		 property servername() {
 			return _name;
 		}



-- 
Simen
Jun 28 2010
prev sibling next sibling parent reply "Steven Schveighoffer" <schveiguy yahoo.com> writes:
On Mon, 28 Jun 2010 16:37:06 -0400, BLS <windevguy hotmail.de> wrote:


 Hi I have a forward reference pb in conjunction with  property.
 Err msg is :
 forward refrence to inferred return type of function call s1.servername.
 any ideas ? beside, where are the  property docs ?
 thanks, bjoern

 final class LoadBalancer {
 	private static LoadBalancer lb;
 	private Server[] servers;
 	
 	static this() {
 		synchronized lb = new LoadBalancer;
 	}
 	
 	private this() {
 		Server s1 = new Server();
 		s1.servername = "Server 1";  // ERROR
 		servers ~= s1;
 	}
 	
 	public static LoadBalancer getLoadBalancer() {
        return lb;
      }

 	 property nextServer() {



Shouldn't this be

 property Server nextServer() {

???


 		return servers[0];
 	}
 		
 	class Server {
 		private string _name, _id;
 		
 		 property servername(string name) {
 			_name = name;
 		}
 		 property servername() {
 			return _name;
 		}
 	}
 }



-Steve
Jun 28 2010
next sibling parent reply Ellery Newcomer <ellery-newcomer utulsa.edu> writes:
On 06/28/2010 03:47 PM, Steven Schveighoffer wrote:

 On Mon, 28 Jun 2010 16:37:06 -0400, BLS <windevguy hotmail.de> wrote:

  property nextServer() {



 Shouldn't this be

  property Server nextServer() {

 ???



auto functions?
Jun 28 2010
next sibling parent Ellery Newcomer <ellery-newcomer utulsa.edu> writes:
On 06/28/2010 03:58 PM, Steven Schveighoffer wrote:

 On Mon, 28 Jun 2010 16:55:01 -0400, Ellery Newcomer
 <ellery-newcomer utulsa.edu> wrote:


 On 06/28/2010 03:47 PM, Steven Schveighoffer wrote:

 On Mon, 28 Jun 2010 16:37:06 -0400, BLS <windevguy hotmail.de> wrote:

  property nextServer() {



 Shouldn't this be

  property Server nextServer() {

 ???



 auto functions?



 I wasn't aware that  property implies auto. I guess that makes sense,
 but I didn't consider it anything but a hint to the compiler about how
 it could be called, not that did anything with the type.

 But I guess it's similar to static...

 -Steve



There are a bunch of modifiers that do.

protection modifiers and maybe align and a few others don't, but pretty 
much everything else does
Jun 28 2010
prev sibling parent reply BLS <windevguy hotmail.de> writes:
On 28/06/2010 22:58, Steven Schveighoffer wrote:

 I wasn't aware that  property implies auto.  I guess that makes sense,
 but I didn't consider it anything but a hint to the compiler about how
 it could be called, not that did anything with the type.



Hm,  this snippet does not compile :
class Server {
	private string _name, _id;

	 property servername(string name) {
		_name = name;
	}
	 property string servername() {
		return _name;
	}
}

remove string from  property and it works.

On the other hand ..
	 property Server nextServer() {
		return servers[0];
	}
compiles fine !
Guess we need the official documents...
Bjoern
Jun 28 2010
parent BLS <windevguy hotmail.de> writes:
On 29/06/2010 00:07, Simen kjaeraas wrote:

 Maybe it's because you haven't added string to the setter? Just grasping
 at straws here.

 --
 Simen



Hi Simen, yes, thats the prob. I just have not found the  property 
docs.. thanks for all the help..
This snippet works now as expected.. D properties are just fine.
Bjoern
import std.stdio;
import std.random;

void main(string[] args)
{
	LoadBalancer b1 = LoadBalancer.getLoadBalancer();
	LoadBalancer b2 = LoadBalancer.getLoadBalancer();
	LoadBalancer b3 = LoadBalancer.getLoadBalancer();

	// Confirm these are the same instance
     if (b1 == b2 && b2 == b3 )  {
     	writeln("Same instance\n");
    	}

	// Next, load 15 requests for a server
   	for (int i = 0; i < 15; i++) {
		string serverName = b1.nextServer.servername;
		writeln("Dispatch request to: " ~ serverName);
       }

}

// D2 thread safe ?????? singleton

final class LoadBalancer {
	private static LoadBalancer lb;
	private Server[] servers;
	
	static this() {
		synchronized lb = new LoadBalancer;
	}
	
	private this() {
		Server s1 = new Server();
		s1.servername = "Server 1";
		s1.id = "";
		Server s2 = new Server();
		s2.servername = "Server 2";
		servers ~= s1;
		servers ~= s2;

	}
	
	public static LoadBalancer getLoadBalancer() {
       return lb;
     }

	 property
	{	
		Server nextServer() { return servers[ uniform(0, 	servers.length) ]; }
	}

	// inner class	
	class Server {
		private string _name, _id;

		 property
		{
			string servername(string sn) { return _name = sn; }
			string servername() { return _name;	}

			string id(string id) { return _id = id; }
			string id() { return _id; }
		}
	}
}
Jun 28 2010
prev sibling parent BLS <windevguy hotmail.de> writes:
On 28/06/2010 22:47, Steven Schveighoffer wrote:

 houldn't this be

  property Server nextServer() {



Ouch, you are right.. Interesting enough that  property nextServer() { 
return ...} compiles without giving any error message..

Anyway it seems to be a forward reference bug. moving the inner Server() 
class in front of LoadBalancer eliminates the error msg.

bjoern
Jun 28 2010
prev sibling next sibling parent BLS <windevguy hotmail.de> writes:
On 28/06/2010 22:37, BLS wrote:

 forward refrence to inferred return type of function call s1.servername.
 any ideas ? beside, where are the  property docs ?
 thanks, bjoern



ok moving the inner Server class (see prev. msg) in front of 
LoadBalancer works.. seems to be a forward reference bug.

class Server {
	private string _name, _id;
		
	 property servername(string name) {
		_name = name;
	}
	 property servername() {
		return _name;
	}
}
final class LoadBalancer {
	private static LoadBalancer lb;
	private Server[] servers;
	
	static this() {
		synchronized lb = new LoadBalancer;
	}
	
	private this() {
		Server s1 = new Server();
		s1.servername = "Server 1";  // NO PROBLEM
	}
...	

}
Jun 28 2010
prev sibling next sibling parent reply "Rory McGuire" <rmcguire neonova.co.za> writes:
On Mon, 28 Jun 2010 22:37:06 +0200, BLS <windevguy hotmail.de> wrote:


 Hi I have a forward reference pb in conjunction with  property.
 Err msg is :
 forward refrence to inferred return type of function call s1.servername.
 any ideas ? beside, where are the  property docs ?
 thanks, bjoern

 final class LoadBalancer {
 	private static LoadBalancer lb;
 	private Server[] servers;
 	
 	static this() {
 		synchronized lb = new LoadBalancer;
 	}
 	
 	private this() {
 		Server s1 = new Server();
 		s1.servername = "Server 1";  // ERROR
 		servers ~= s1;
 	}
 	
 	public static LoadBalancer getLoadBalancer() {
        return lb;
      }

 	 property nextServer() {
 		return servers[0];
 	}
 		
 	class Server {
 		private string _name, _id;
 		
 		 property servername(string name) {
 			_name = name;
 		}
 		 property servername() {
 			return _name;
 		}
 	}
 }



Only place I've seen  property docs is in TDPL
Jun 28 2010
parent BLS <windevguy hotmail.de> writes:
On 28/06/2010 23:00, Steven Schveighoffer wrote:

 http://www.digitalmars.com/d/2.0/function.html#property-functions

 -Steve



Makes sense :) thanks
Jun 28 2010
prev sibling next sibling parent "Steven Schveighoffer" <schveiguy yahoo.com> writes:
On Mon, 28 Jun 2010 16:55:01 -0400, Ellery Newcomer  
<ellery-newcomer utulsa.edu> wrote:


 On 06/28/2010 03:47 PM, Steven Schveighoffer wrote:

 On Mon, 28 Jun 2010 16:37:06 -0400, BLS <windevguy hotmail.de> wrote:

  property nextServer() {



 Shouldn't this be

  property Server nextServer() {

 ???



 auto functions?



I wasn't aware that  property implies auto.  I guess that makes sense, but  
I didn't consider it anything but a hint to the compiler about how it  
could be called, not that did anything with the type.

But I guess it's similar to static...

-Steve
Jun 28 2010
prev sibling next sibling parent "Steven Schveighoffer" <schveiguy yahoo.com> writes:
On Mon, 28 Jun 2010 16:55:44 -0400, Rory McGuire <rmcguire neonova.co.za>  
wrote:


 On Mon, 28 Jun 2010 22:37:06 +0200, BLS <windevguy hotmail.de> wrote:


 beside, where are the  property docs ?



 Only place I've seen  property docs is in TDPL



http://www.digitalmars.com/d/2.0/function.html#property-functions

-Steve
Jun 28 2010
prev sibling parent "Simen kjaeraas" <simen.kjaras gmail.com> writes:
BLS <windevguy hotmail.de> wrote:


 Hm,  this snippet does not compile :
 class Server {
 	private string _name, _id;

 	 property servername(string name) {
 		_name = name;
 	}
 	 property string servername() {
 		return _name;
 	}
 }

 remove string from  property and it works.



Maybe it's because you haven't added string to the setter? Just grasping
at straws here.

-- 
Simen
Jun 28 2010