When should you use plus, minus, times functions instead of using the operators in Kotlin?

Question

I cannot think of a case where using the Kotlin built-in plus, minus, times etc. functions would return a different result from just using the corresponding operators (+, -, *). Why would you ever want to use these functions in your Kotlin code?

Answer 1

Just in case you aren't aware, these are operator overloads. The named functions are how the operators' functionality is defined.

There is a case for using the named versions. The function calls don't pay attention to operator precedence and are evaluated sequentially if you chain them.

val x = 1
val y = 2
val z = 3

println(x + y * z)          // equivalent to 1 + (2 * 3) -> 7
println(x.plus(y).times(z)) // equivalent to (1 + 2) * 3 -> 9

This could be clearer than using the operators if you have a lot of nested parentheses, depending on the context of the type of math you're doing.

result = ((x - 7) * y - z) * 10

// vs

result = x.minus(7).times(y).minus(z).times(10)

It's not really applicable for basic algebra like this, but you might have classes with operator overloads where the logic can be more easily reasoned through with the sequential approach.