org.partiql.lang.ast.IsTransformedOrderByAliasMeta.kt Maven / Gradle / Ivy
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An implementation of PartiQL for the JVM written in Kotlin.
/*
* Copyright 2019 Amazon.com, Inc. or its affiliates. All rights reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License").
* You may not use this file except in compliance with the License.
* A copy of the License is located at:
*
* http://aws.amazon.com/apache2.0/
*
* or in the "license" file accompanying this file. This file 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 org.partiql.lang.ast
import org.partiql.lang.eval.visitors.OrderBySortSpecVisitorTransform
/**
* A [Meta] to help the [OrderBySortSpecVisitorTransform] to know when the OrderBy SortSpec has already been transformed. It
* essentially helps to turn
*
* ```SELECT a + 1 AS b FROM c ORDER BY b```
*
* into
*
* ```SELECT a + 1 AS b FROM c ORDER BY a + 1```
*
* even when there are multiple transforms over the AST.
*/
class IsTransformedOrderByAliasMeta private constructor() : Meta {
override val tag = TAG
companion object {
const val TAG = "\$is_transformed_order_by_alias"
val instance = IsTransformedOrderByAliasMeta()
}
}