Unwrapping & Chaining

Drift permits members chaining.

class A(value: Int)

let instance = A()
print(instance.value)       // Here, instance.value is a chain to access 
                            // value from the instance object

Forced Unwrapping

warning

At this moment, Drift does not implement forced unwrapping

let a: String? = "hello"
let b: String = a!          // '!' operator removes the nullable typing

// and forced unwrapping in a chain

nullableMember!.child

Sometimes, members can be nullable. A direct chaining from them could throw a runtime exception in case of a Null value.

let username: String? = null
print(username.length)      // It will throw a runtime exception, 
                            // username is Null, length is an unknown member

If you are sure that the member will not have Null as value, you can use the ! operator. It is used to unwrap nullable behavior from the member type: String? -> String.

warning

Unwrap a member which has Null as value will throw a runtime exception: Null cannot be unwrapped.

Optional Chaining

warning

At this moment, Drift does not implement optional chaining.

nullableMember?.child
// If nullableMember is not null, the chain is executed, else not.

Optional Chaining permits doing a chain if the member is not Null.