Android Development with Kotlin

The let function

The let function is preferred when we want to use standard functions as if they are extension functions in stream processing:

    val newNumber = number.plus(2.0) 
       .let { pow(it, 2.0) } 
       .times(2) 

Like other extensions, it can be combined with a save call operator:

    val newNumber = number?.plus(2.0) 
       ?.let { pow(it, 2.0) } 

The let function is also preferred which we just want to unpack a nullable read-write property. In this situation, it is not possible to smart cast this property and we need to shadow it, like in this solution:

    var name: String? = null 
 
    fun Context.toastName() { 
        val name = name
        if(name != null) { 
            toast(name) 
        } 
    }   

The name variable is the shadowing property name, what is necessary if name is a read-write property, ...