Kotlin let the coder call a function or a method without using the dot notation:
class Person (age : Int) {
infix isOlderThan(p : Person) : Boolean {
return age > p.age
}
}
Person a = Person (34)
Person b = Person (34)
val ret = a isOlderThan b
The infix functions have only one parameter with no default value
miniguide 