How would you guys recomend to use elvis operator ...

# codingconventions

[gabrielfv]

How would you guys recomend to use elvis operator on long expressions with line breaks?

val a = foo.computeBar(Baz::class.java).fetchFirst() ?:
        return@thisComputationFun

or

val a = foo.computeBar(Baz::class.java).fetchFirst()
        ?: return@thisComputationFun

or none at all? The IDE has recomended me to do this in place of the classic if (a == null) return@thisComputationFun

[diesieben07]

My intuition says

val a = foo.computeBar(Baz::class.java)
           .fetchFirst() ?: return@thisComputationFun

[gabrielfv]

With the return in the same identation?

[deviant]

val a = foo
    .computeBar(Baz::class.java)
    .fetchFirst()
    ?: return@thisComputationFun

[diesieben07]

That looks very weird to me, but I guess it could work

[gabrielfv]

If I had to choose, would be a mix of both:

val a = foo.computeBar(Baz::class.java)
        .fetchFirst() ?:
        return@thisComputationFun

[diesieben07]

I have to disagree with that, if you're just scanning it's easy to miss and you see "oh this just returns" instead "this returns on a condition"

[gabrielfv]

Well, indeed

[gabrielfv]

but on a similar identation to the val a it looks like its just returns as well. On a similar level of a .method() it draws some more attention.

[gabrielfv]

Another alternative identation might work as well, but I really can't figure a better one

[bdawg.io]

I hate deep nesting (it’s high churn in your code just waiting to happen). I also dislike mixing the location of signal symbols (. to invoke a method and ?: to signal an elvis operation). My vote would be

1. val a = foo.computeBar(Baz::class.java).fetchFirst()
2.     ?: return@thisComputationFun

or

1. val a = foo
2.     .computeBar(Baz::class.java)
3.     .fetchFirst()
4.     ?: return@thisComputationFun

(although I agree with intellij about breaking out this logic from your assignment operator)