To simplify the compiler code

Question

Florian · Answer

I mean why do normal operators need these functions in the first place

Florian · Answer

Java doesnt have that

karelpeeters · Answer

Another way to think about it there are no normal operators there is only operator overloading

karelpeeters · Answer

Java doesn t have operator overloading so they were forced to create special cases for primitives and strings

karelpeeters · Answer

Kotlin can go the elegant route and define everything in Kotlin source code which simplifies compiler code

Florian · Answer

Ok I think I get it

Florian · Answer

Thank you

Florian · Answer

Just one more thing I don t get

Florian · Answer

where are the implementation for these methods

Florian · Answer

they are just declared in the file

karelpeeters · Answer

I can t really find it but it s just somewhere deep in the compiler source code

karelpeeters · Answer

But there s no real implementation it just converts to an `iadd` bytecode operation on the JVM or a `+` on JS

Florian · Answer

I want to pick this up one more time

Florian · Answer

I understand WHY they don t have bodies but how can they be DECLARED inside a kt file without a body

Florian · Answer

If the class is not abstract

Florian · Answer

Do those files not follow the same compiler rules

karelpeeters · Answer

Okay I spent some time tracking it down in the compiler source here it is for the JVM <https github com JetBrains kotlin blob 5e3a11db8e2f525dc43a722fa4d8cf7e7858a409 compiler ir backend jvm src org jetbrains kotlin backend jvm intrinsics IrIntrinsicMethods kt L113>

karelpeeters · Answer

If you follow that down it expands to a list of intrinsics one for each primitive type

karelpeeters · Answer

So no they don t follow the normal rules

karelpeeters · Answer

`IADD` is literally just an integer so that s what it actually ends up as bytecode

Florian · Answer

Oh wow thank you for the effort

karelpeeters · Answer

I wanted to know as well

karelpeeters · Answer

It had been on my todo list for 3 months smile

karelpeeters · Answer

Out of curiosity why do you care so much not trying to be discouraging being curious is good

Florian · Answer

Because I have a Kotlin beginner tutorial running on my YouTube channel

Florian · Answer

So I need to know some details that I usually wouldn t care about

karelpeeters · Answer

Hmm I see I void just avoid it entirely no one asks why `+` in Java works either or `Object hashcode` or that kind of stuff Same in Pyhton

Florian · Answer

In one of the 1st parts we have looked into the Primitives kt file and now we learn about functions so I want to clarify why the functions in there don t have bodies

Florian · Answer

To avoid confusion

Florian · Answer

I don t want to explain it in detail I just want to mention it

Florian · Answer

Often these small details require most of the research time

Florian · Answer

And I am not a professional I always just learn in the process

Florian · Answer

As you can tell from my noob questions

karelpeeters · Answer

I see