This is another feature of Kotlin that is intended for creating DSLs. Infix functions are like normal functions, but they can be called without the dot and parentheses. To declare an infix function, you have to place the infix keyword before the fun keyword. Here's an example:

class Employee {
    infix fun payout(salary: Int) {
        print("Employee was paid: $salary")
    }
}

Now, we can call the payout function without the dot and parentheses:

val employee = Employee()
employee payout 3500

These conditions have to be satisfied to use the infix keyword:

• Function has to have a single parameter
• Function has to be a member function or an extension function
• Parameters cannot be variable arguments
• Parameters cannot have a default value