nikita.movshin
65244b4bea
Change the copyright from "JetBrains s.r.o." to "JetBrains s.r.o. and Kotlin Project contributors" Update only 2 lines copyright.
38 lines
1.5 KiB
Kotlin
38 lines
1.5 KiB
Kotlin
/*
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* Copyright 2010-2018 JetBrains s.r.o. and Kotlin Programming Language contributors.
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* Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
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*/
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package kotlin
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import kotlin.annotation.AnnotationTarget.*
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import kotlin.experimental.ExperimentalTypeInference
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/**
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* Allows to infer generic type arguments of a function from the calls in the annotated function parameter of that function.
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*
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* When this annotation is placed on a generic function parameter of a function,
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* it enables to infer the type arguments of that generic function from the lambda body passed to that parameter.
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*
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* The calls that affect inference are either members of the receiver type of an annotated function parameter or
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* extensions for that type. The extensions must be themselves annotated with `@BuilderInference`.
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*
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* Example: we declare
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* ```
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* fun <T> sequence(@BuilderInference block: suspend SequenceScope<T>.() -> Unit): Sequence<T>
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* ```
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* and use it like
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* ```
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* val result = sequence { yield("result") }
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* ```
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* Here the type argument of the resulting sequence is inferred to `String` from
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* the argument of the [SequenceScope.yield] function, that is called inside the lambda passed to [sequence].
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*
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* Note: this annotation is experimental, see [ExperimentalTypeInference] on how to opt-in for it.
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*/
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@Target(VALUE_PARAMETER, FUNCTION, PROPERTY)
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@Retention(AnnotationRetention.BINARY)
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@SinceKotlin("1.3")
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@ExperimentalTypeInference
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public annotation class BuilderInference
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