Auto-Implemented properties

[Jacob Carlborg]

On 2013-01-05 23:40, michaelc37 wrote:
> i was trying to make a D template to mimic auto-implemented
> properties in c#.
>
> I think i got it to work but when i tried to give the template a
> more meaning full name like AutoImplementedProperty i get a
> compile error "a.title is not an lvalue".
> Is this a bug?
> Is there a more suitable way of doing this?
>
> c# e.g:
> class Bar
> {
>      public string Title { get; set; }
> }
>
> my attempt:
> class Bar
> {
>      alias autoproperty!(string, "get", "set") title
> }
>
> template autoproperty(T, args...)
> {
>      import std.typetuple;
>      @property
>      {
>          private T _name;
>          static if (args.length)
>          {
>              static if (staticIndexOf!("get", args) > -1)
>              {
>                  public T autoproperty()
>                  {
>                      return _name;
>                  }
>              }
>
>              static if (staticIndexOf!("set", args) > -1)
>              {
>                  public void autoproperty(T value)
>                  {
>                      _name = value;
>                  }
>              }
>
>          }
>      }
> }
>
> void main(string[] args)
> {
>      Bar a = new Bar();
>      a.title = "asf";
>      writefln(a.title);
>
>      return;
> }

This won't work like you think it will. All instances of "Bar" will 
share the same "_name" variable.

You need to use a mixin. This pass:

void main ()
{
     Bar a = new Bar();
     a.title = "asf";

     Bar b = new Bar;
     assert(b.title == a.title);
}


-- 
/Jacob Carlborg