ComposableOpenTarget.kt
/*
* Copyright 2021 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package androidx.compose.runtime
/**
* The [Composable] declares that it doesn't expect a particular applier. See
* [ComposableTarget] for more details on what appliers a [Composable] function expects.
*
* In a [Composable] function, all the open composable appliers with the same applier index must
* have the same name.. [CompositionLocalProvider], for example, can use [ComposableOpenTarget]
* to declare that its content parameter must have the same applier as it receives, since it
* calls the content parameter directly, but it could be any applier. [ComposableOpenTarget], in
* this way, works like an open type parameter for the type of applier used by the implied
* composer parameter.
*
* Th [ComposableOpenTarget] is unlikely to be required explicitly as it is inferred
* automatically by the Compose compiler plugin. See [ComposableTarget] for more details on how
* attributes are inferred.
*
* @param index The index of the open applier parameter. All open appliers with the same
* non-negative index in the same declaration must have the same name. All negative indexes are
* considered anonymous and can match any applier. If the [index] is only used once in a
* declaration it can also match any applier but it is recommended to use a negative index
* instead or just leave the annotation off as a missing annotation is equivalent to an anonymous
* applier.
*/
@Retention(AnnotationRetention.BINARY)
@Target(
AnnotationTarget.FUNCTION,
AnnotationTarget.PROPERTY_GETTER,
AnnotationTarget.TYPE,
AnnotationTarget.TYPE_PARAMETER,
)
annotation class ComposableOpenTarget(val index: Int)