How to define new operator in Kotlin?

I works with Math. Android Studio forbids to use ^ with quotes. So I've defined v operator (^ upside down). Is it ugly? Yes, but it is best than thons of typecasting and pow notation.

inline infix fun Double.v(exponent: Int): Double = this.pow(exponent)
inline infix fun Double.v(exponent: Long): Double = this.pow(exponent.toDouble())
inline infix fun Double.v(exponent: Double): Double = this.pow(exponent)
inline infix fun Int.v(exponent: Int): Double = this.toDouble().pow(exponent)
inline infix fun Int.v(exponent: Long): 
      Double = this.toDouble().pow(exponent.toDouble())
inline infix fun Int.v(exponent: Double): Double = this.toDouble().pow(exponent)
inline infix fun Long.v(exponent: Int): Double = this.toDouble().pow(exponent)
inline infix fun Long.v(exponent: Long): 
      Double = this.toDouble().pow(exponent.toDouble())
inline infix fun Long.v(exponent: Double): 
      Double = this.toDouble().pow(exponent)

inline usage generates no extra load in runtime, even inside heavier loops.

Unfortunately, the damaged operator precedence forces you to surround the power operation with parentheses. And the compiler forces you flank with spaces.

After all, what gives the best look?

This?

var k=2  
...
println((k v 5)+3)

Or this?

var k=2
 ... 
println(k.toDouble().pow(5) + 3)

I vote on the fist option!.

Unfortunately, you cannot define new operators, there's only a predefined set of those that can be overloaded. Some operators might be added to this set later, there's an open issue for that in the Kotlin issue tracker.

However, you can use backticked names to define infix extension functions which look like operators (much less pretty though):

infix fun Int.`^`(exponent: Int): Int = ... 

Usage:

5 `^` 3

Note that infix functions have precedence lower than that of operators, thus

1 + 1 `^` 3 == 8