new DIP5: Properties 2

[Benji Smith]

> On Mon, Jul 27, 2009 at 4:34 PM, Chad
>> This seems to me like it adds more syntactic clutter than adding a
>> keyword would:
>>
>> PropertyDecl:
>>        PropertyGetter
>>        PropertySetter
>>
>> PropertyGetter:
>>        Type 'opGet_' Identifier '(' ')'
>>
>> PropertySetter:
>>        Type 'opSet_' Identifier '(' Type ')'
>>
>>

Jarrett Billingsley wrote:
> Nono,

<snip>

> they're just functions with "magical" names.

I agree with Chad. The opGet_Xxxxx syntax is terrible, with both 
syntactic and semantic clutter. To whit:

1) This convention has four syntactic parts: "op", "Get|Set", "_", and 
an identifier. Adding a new keyword (like "property") would only add one 
syntactic element to the declaration.

2) A property is not an operator. So the "op" prefix is lying to you.

3) The existence of "magical" identifiers complicates the language 
design. Because the rules that apply to those magical identifiers is 
different than the rules applying to non-magical identifiers.

There's nothing wrong with the mechanics of the proposal. I especially 
like how it allows the getter/setter to have different protection 
attributes, and that it allows each function to be overridden 
separately. You could even implement the getter in a read-only 
superclass and implement the setter in a read-write subclass. Nice!

But I think the same thing can be more elegantly written using the 
"property" keyword:

   private int _x;
   public property int X() { return _x; }
   protected property X(int value) { _x = value; }

The only disadvantage I see there is the introduction of a keyword. And 
that's definitely a disadvantage. But, compared to the "op" syntax, I 
think it's the lesser of two evils.

--benji