I agree with Adam's view and I really think @property is a good
thing.
APIs have to specify their semantics and clearly distinguish
properties from functions, which may be implemented similarly but
*mean* different things. Basically a property is a *thing* or a
characteristic, normally a noun, whereas a property is an action,
normally a verb.
As a special case, a property can be a delegate or function, and
calling it with () would apply the parens to the delegate (which
the user is explicitly calling), but not to the property.
Properties as they are can also be used to emulate "indexed
properties", as in other languages. If a property's type is a
struct that implements [] and []= then we can do:
image.pixels[x,y] = Rgb(255,0,0);
And yes, I think properties should always be called ["used" I
would rather say] without parens, and functions always be called
with parens. Isn't it like this in other languages, e.g. C#, BTW?
But anyway as I don't develop the compiler, I speak from a
distance, and I'm not aware of the implementation complications
there may be...
On Thursday, 24 January 2013 at 13:43:34 UTC, Adam D. Ruppe wrote:
No, god no. This would break code AGAIN and still not fix the
problems, instead introducing new ones!
I think any property proposal that talks about parenthesis in
the definition is wrong. With a good definition, the existing
type system will handle the parenthesis.
@property int foo() { return 10; }
foo(); // the correct error is "type int is not callable"
This is the key point:
A property is NOT a function as far as user code is concerned.
That's just an implementation detail.
As far as user code is concerned, a property IS its return
value.
If you implement that, leaving all the other rules in the
language exactly the same, we'll actually fix some problems
without breaking the overwhelming bulk of existing code.
Fixing the rest of the problems is then about getting op*Assign
to work right.
Functions not marked @property should NOT change AT ALL from
what we have now. I am against removing the existing optional
parenthesis rule, and I am against removing the @property
decoration.
Fix it this time, don't break it in a different place.
