new A().b() currently requires extra brackets/parentheses

[Timon Gehr]

On 09/09/2012 02:49 PM, Ben Davis wrote:
> Hi,
>
> I'm trying to define an API in D where an object can be instantiated and
> then set up inline. I have various methods that return 'this' so that
> they can be used inline in this way. For example:
>
> dialogue=new GuiDialogue([
>      (new GuiLabel(titleText)).setLayoutHint(GuiLayoutHint.TOP),
>      fileNameInput.setLayoutHint(GuiLayoutHint.TOP),
>      currentDirectoryLabel.setLayoutHint(GuiLayoutHint.TOP),
>      confirmButton,
>      new GuiButton("Cancel",delegate {dialogue=null;}),
> ]);
>
> D's syntax currently requires me to put the new A() part in brackets. So
> instead of
>
> new A().b()
>
> I have to write
>
> (new A()).b()
>
> If I don't do that, then the error is "found . when expecting ," - which
> sounds as if it's already decided it's finished reading the expression,
> so there isn't a problem with ambiguity. (I suppose if the brackets are
> optional, then "new A.b()" would be ambiguous, but this is no different
> from the 'else' binding problem.)
>
> So - is this something that could be relaxed?
>
> Thanks,
>
> Ben :)

I think so. Probably it is just a bug. (the spec does not indicate that
it is illegal iirc.) Maybe you can even fix it yourself, the parser
should be quite hackable.