Curios, for constants you use 'const val', why not just const?

# getting-started

[Ben Edwards]

Curios, for constants you use 'const val', why not just const?

[Chris Lee]

the Kotlin syntax for constants is const val. These are for values that are known at compile time, and are inlined into where they are used. This differs from val that assigns values at runtime.

[Stephan Schroeder]

Ben has a point, why not just const 🤔 It's not like you could have a const var , so composability isn't a thing here and the chosen solution is longer which unfortunately reminds me of Java's final var .

[ephemient]

const should be left as a modifier to keep future uses open

[Ben Edwards]

My point is the val does not give you anything. const var would be nonsense. I'm curious why the people who created the syntax decided on it.

[ephemient]

const fun might have a future meaning

[ephemient]

the design is not final but you can see some plans, https://youtrack.jetbrains.com/issue/KT-14652

[Stephan Schroeder]

so why would you need const x = 5 and ``const val x = 5`` in the language. My uneducated impression is that you could always reinterprete a runtime const x = 5 (with the current const val semantics) to also have a comptime semantic without breaking any existing code because comptime doesn't exist yet.

[Chris Lee]

presently, Kotlin constants (const val) are only evaluated at compile time and do not exist at runtime.

[Stephan Schroeder]

so? how is that different from something that would be denoted by only const in other languages?

[ephemient]

Chris: that's not totally true, they still exist at runtime even though all static references are inlined, at least on JVM

[ephemient]

Stephan: not sure which languages you're comparing to
Python/Swift - no const
Java - no `const`; final qualifier is overloaded
C/C++/Objective-C/D - const is qualifier, but means something different
Go/JS - const is declaration, but means something different
Rust - the only one where const has a meaning like const val in Kotlin

[Stephan Schroeder]

@ephemient as far as I know, comptime values/functions in Zig are available at compile-time and runtime.
I just got an idea, that might explain why const val = 5 might be better idea than simply the keyword const x = 5 . const is probably composable after all, not with var but with fun (possibly in the future)!?!
I do prefer the idea of using const val and const fun over const and const fun.