Andrey Breslav
42 lines
1.6 KiB
Plaintext
42 lines
1.6 KiB
Plaintext
To denote the current _receiver_, we use *this* expressions:
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* In a member of a [class|Classes and Inheritance], *this* refers to the current object of that class
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** *this{*}{{<Supertype>}} is used to qualified calls to supertype's implementations of members, see [Classes and Inheritance#Overriding rules]
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* In an [extension function|Extension functions] or an [extension function literal|Function literals#Extensions], *this* denotes the _receiver_ parameter that is passed on the left-hand side of a dot.
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If *this* has no qualifiers, it refers to the _innermost enclosing scope_. To refer to *this* in other scopes, _label qualifiers_ are used:
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{anchor:qualified}
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h3. Qualified {{this}}
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To access *this* from an outer scope (a [class|Classes and Inheritance], or [extension function|Extension functions], or labeled [extension function literal|Function literals#Extensions]) one writes *this{*}{{@label}} where {{@label}} is a [label|Returns and jumps] on the scope {{this}} is meant to be from:
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{jet}
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class A { // implicit label @A
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class B { // implicit label @B
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fun Int.foo() { // implicit label @foo
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val a = this@A // A's this
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val b = this@B // B's this
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val c = this // foo()'s receiver, an Int
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val c1 = this@foo // foo()'s receiver, an Int
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val funLit = {String.() -> // implicit label @
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val d = this // funLit's receiver
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val d1 = this@ // funLit's receiver
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}
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val funLit2 = { (s:String) ->
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val d1 = this // foo()'s receiver, since enclosing function literal doesn't have any receiver
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}
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}
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}
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}
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{jet}
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h3. What's next
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* [Tuples]
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* [Type casts]
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