This Expression
This Expression
To denote the current receiver, we use this expressions:
- In a member of a class, this refers to the current object of that class
- In an extension function or a function literal with receiver, this denotes the receiver parameter that is passed on the left-hand side of a dot.
If this has no qualifiers, it refers to the innermost enclosing scope. To refer to this in other scopes, label qualifiers are used:
Qualified this
To access this from an outer scope (a class, or extension function, or labeled function literal with receiver) we write this@label
where @label
is a label on the scope this is meant to be from:
class A { // implicit label @A inner class B { // implicit label @B fun Int.foo() { // implicit label @foo val a = this@A // A's this val b = this@B // B's this val c = this // foo()'s receiver, an Int val c1 = this@foo // foo()'s receiver, an Int val funLit = lambda@ fun String.() { val d = this // funLit's receiver } val funLit2 = { s: String -> // foo()'s receiver, since enclosing lambda expression // doesn't have any receiver val d1 = this } } } }
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https://kotlinlang.org/docs/reference/this-expressions.html