PROPOSAL: Elvis operator (original) (raw)

Marek Kozieł develop4lasu at gmail.com
Sat Mar 21 07:23:32 PDT 2009

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/

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