property-like data members

[spir]

On Mon, 03 Jan 2011 10:27:17 -0500
"Steven Schveighoffer" <schveiguy at yahoo.com> wrote:

> On Mon, 03 Jan 2011 09:56:30 -0500, spir <denis.spir at gmail.com> wrote:
> 
> > On Mon, 03 Jan 2011 08:34:42 -0500
> > "Steven Schveighoffer" <schveiguy at yahoo.com> wrote:
> >
> >> Yes, just use a data member:
> >>
> >> struct MyRange {
> >>     int front;
> >>     bool empty;
> >>     void popFront();
> >> }
> >>
> >> A property is actually supposed to work just like a field.
> >>
> >> There is no need for new syntax.
> >
> > Hum, does not work by me (else I would not have posted ;-)
> > The compiler rejects the code complaining for missing opApply (which I  
> > interpret as meaning it does not recognize a range in such an  
> > interface). indeed, it works if manually implement iteration like for  
> > instance:
> > 	while (! coll.empty) {
> > 	    auto element = coll.front;
> > 	    use(element);
> > 	    coll.popFront();
> > 	}
> > But then there no property in play (I mean the compiler does not expect  
> > a property set implementing a range).
> 
> That's a bug.  isInputRange!S returns true.
> 
> There's nothing in the spec that says foreach requires those elements to  
> be functions.  In fact, empty *does* work as a normal field, i.e. this  
> struct is foreachable:
> 
> struct S
> {
>     @property int front() {return 0;}
>     bool empty;
>     void popFront() {empty = true;}
> }
> 
> Filed:
> 
> http://d.puremagic.com/issues/show_bug.cgi?id=5403
> 
> -Steve

All right. great that we can do that (provide a plain data member where a property is expected).

denis
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