What is the point of `ByteArray`, `IntArray`, `CharArray` etc? why not just `Array<Byte>`, `Ar...

# announcements

[Hullaballoonatic]

What is the point of ByteArray, IntArray, CharArray etc? why not just Array<Byte>, Array<Int>, Array<Char>. I know that Java does treat primitive arrays differently from object arrays, but couldn't Kotlin do us a solid and smoosh them all into just Array<T>?

[Derek Peirce]

That gets problematic when Array<Int> sometimes means Integer[] (when it's Array<T> and learns of its type at runtime) and other times means int[].

[gildor]

Than it wouldn't be possible to distinguish between primitive and boxed arrays in source code, they are incompatible on binary level

[Hullaballoonatic]

Also, why does kotlin throw away the distinction between int -> Int and Integer -> Int but not int[] -> IntArray and Integer[] -> Array<Int>?

[Hullaballoonatic]

if it can throw away the former, why not the latter?

[Derek Peirce]

Int refers to int except when generics or nullability are involved, in which case it becomes Integer. Converting between the two is trivial (relatively), so there's no issue. However, converting between int[] and Integer[] can be prohibitively expensive.

[gildor]

Also from Java it's not a problem to pass int to Integer or vice versa,, but primitive array are not interchangeable with Object arrays of corresponding types.
One more reason for this, that you just cannot write a function that doesn't involve boxing for generic array, which essentially makes primitive arrays useless, if you need primitive array, you don't want to have boxing

Think about primitive arrays as low level abstraction that useful in performance critical cases and provides efficient low level access to memory, but shouldn't be used in most other