@property needed or not needed?

[Maxim Fomin]

On Monday, 28 January 2013 at 17:41:07 UTC, Dicebot wrote:
> On Monday, 28 January 2013 at 17:20:13 UTC, Maxim Fomin wrote:
>> ...
>
> Those are C rules, do not forget it. Thus value of (b = c) IS 
> equivalent to value of b when lvalues are considered. And you 
> are perfectly allowed to forget about c and do a = b after b = 
> c was evaluated. It is plain old data, after all, if b = c is 
> not interchangeable with b, something is wrong.
>
> At least I see nothing in standard that proves your statement.
>

You are still breaking expression a = b = c and mixing terms of 
value of expression and expression itself.

>>
>> Applying your logic:
>>
>> Left operand for a = (b = c) is a. Thus a has value of (b = 
>> c). Value of b = c is b.setter(c.getter()).
>
> You are applying it wrong. Thing of it as of recursion.

I applied exactly as you did.

> 1) evaluate "a = b = c"
> 2) evaluate a.set( (b = c).get() ), result of 1 will be a.get() 
> ( if needed )

.get() is wrong here. Expression is a = b = c, not a = ( (b = 
c).get ))

> 3) evaluate "b = c"
> 4) evaluate b.set( c.get() ), result of 3 will be b.get() ( if 
> needed )
> 5) combine: a.set( b.set( c.get() ), b.get() )

This breaks requirement from quoted paragraph that side effects 
are sequenced after value computations on both operands: 
computing value of b (b.get) happened after updating value 
(b.set).

In Bugzilla there were close to this case like following (do not 
remember #):

struct S { int a; int b; int c; }
...
S s1, s2;

s1 = { 1, s1.a 2 }

Compiler was wrongly applied side effects before evaluating s1.a 
(it should be zero, not 1).

> Note that evaluation order for comma expression is defined, so 
> "c.get() ), b.get()" is valid and correct code.

Well, discussion went repetitive - I still insists that a = b = c 
should be evaluated as it is currently a.set(b=c) = > 
a.set(b.set(c)) => a.set(b.set(c.get)). By the way, this C# 
program also behaves as I understand rules:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

class S
{
     int _i;
     public int i
     {
         get { Console.WriteLine("getter"); return _i; }
         set { Console.WriteLine("setter"); _i = value; }
     }
}

namespace ConsoleApplication1
{
     class Program
     {
         static void Main(string[] args)
         {
             S s1 = new S() , s2 = new S(), s3 = new S();
             s1.i = s2.i = s3.i;
         }
     }
}

getter
setter
setter