A range is defined as an interval that has a start value and an end value. Any types which are comparable can be used to create a range, which is done using the .. operator:

    val aToZ = "a".."z" 
    val oneToNine = 1..9 

Once a range is created, the in operator can be used to test whether a given value is included in the range. This is why the types must be comparable. For a value to be included in a range, it must be greater than or equal to the start value and less than or equal to the end value:

    val aToZ = "a".."z" 
    val isTrue = "c" in aToZ
    val oneToNine = 1..9 
    val isFalse = 11 in oneToNine 

Integer ranges (ints, longs, and chars) also have the ability to be used in a for loop. See the section on For loops for further details.

There are further library functions to create ranges not covered by the .. operator; for example, downTo() will create a range counting down and rangeTo()will create a range up to a value. Both of these functions...