DIP4: Properties

[Michel Fortin]

On 2009-07-25 06:10:09 -0400, Michiel Helvensteijn 
<m.helvensteijn.remove at gmail.com> said:

> It's a little better. But there's still ambiguity:
> 
> interface I {
>     int foo;
>     int opSet_foo(int);
> }
> 
> foo = 5; // which foo is used?

In the other thread, I suggested this, which could aleviate the problem:

	int foo.opGet();        // getter
	void foo.opAssign(int); // setter

with some support from the compiler.

It could even be exteded to support more:

	int foo.opIndex(int); // foo[1];
	void foo.opAddAssign(int); / foo += 1;
	void foo.invert(); // special function attached to property

Basically, all you need to implement properties is not a dedicaced 
"property" syntax, it's a syntax to implement some kind of local 
namespace, and am "opGet" or "opValue" operator for representing the 
local namespace. It could also be expressed like this:

	namespace foo {
		int opGet(); // getter
		void opAssign(int); // setter
		...
		int opIndex(int); // foo[1];
		void opAddAssign(int); / foo += 1;
		void invert(); // special function attached to property
	}

In both cases, the result would be the same:

	foo = 1; // same as foo.opAssign(1);
	return foo; // same as return foo.opGet();

-- 
Michel Fortin
michel.fortin at michelf.com
http://michelf.com/