PROPOSAL: Elvis operator

[Marek Kozieł]

2009/3/21 Olivier Chorier <lapsus63 at gmail.com>

> I initially thought it was a good idea, but after a bit reflection, I don't
> think it is a real 'plus' compared with the ternary operator.
>
> For example, how would you simplify those lines of code (assuming the coder
> loves ternary operator) :
>
> int value = object == null ? -1 :
>                (object.getSubObject() == null ? -1 :
>                        (object.getSubObject().getValue() == null ? -1 :
>                               object.getSubObject().getValue()));
>
> Does somebody has an idea (excepting using an ugly try-catch statement) to
> write this much clearer ?
> (sorry for code indentation)
>
>
> 2009/3/21 Stephen Colebourne <scolebourne at joda.org>
>
>
>
> You wrong, this should look like:

int value = object.?getSubObject().?getValue() ?: -1

But there is another problem that I would like to see handled:

What if we have default SubObject which we can use when main one is null,
and it's ugly generic:

SubObject<FirstType,SecondType,TirdType,.......> subObject =
object.?getSubObject() ?: default;

int value = subObject.?getValue() ?: -1;

// here we can use subObject

now same in other syntax:

int value = object.?getSubObject() ?:( subObject )  .?getValue() ?: -1;

and other syntax:

object.?getSubObject() :: subObject;

int value = ( subObject ?: default ).?getValue() ?: -1;

// here we can use subObject

and other:

int value = ( object.?getSubObject() ?: default ).?getValue() ?: -1;

Consider witch is easier to read.
-- 
Pozdrowionka. / Regards.
Lasu aka Marek Kozieł

http://lasu2string.blogspot.com/