org.neo4j.cypher.internal.rewriting.rewriters.GQLAliasFunctionNameRewriter.scala Maven / Gradle / Ivy

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Tree rewriting support, and AST rewriters for the Cypher query language

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/*
 * Copyright (c) "Neo4j"
 * Neo4j Sweden AB [https://neo4j.com]
 *
 * 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 org.neo4j.cypher.internal.rewriting.rewriters

import org.neo4j.cypher.internal.ast.semantics.SemanticState
import org.neo4j.cypher.internal.expressions.FunctionInvocation
import org.neo4j.cypher.internal.expressions.FunctionName
import org.neo4j.cypher.internal.rewriting.conditions.FunctionInvocationsResolved
import org.neo4j.cypher.internal.rewriting.conditions.GQLAliasFunctionNameRewritten
import org.neo4j.cypher.internal.rewriting.rewriters.factories.ASTRewriterFactory
import org.neo4j.cypher.internal.util.AnonymousVariableNameGenerator
import org.neo4j.cypher.internal.util.CancellationChecker
import org.neo4j.cypher.internal.util.CypherExceptionFactory
import org.neo4j.cypher.internal.util.Rewriter
import org.neo4j.cypher.internal.util.StepSequencer
import org.neo4j.cypher.internal.util.StepSequencer.Condition
import org.neo4j.cypher.internal.util.bottomUp
import org.neo4j.cypher.internal.util.symbols.ParameterTypeInfo

/**
 * Rewrites GQL Alias functions to their Cypher equivalent
 * e.g
 * char_length(STRING) :: INTEGER -> character_length(STRING) :: INTEGER
 * upper(STRING) :: STRING -> toUpper(STRING) :: STRING
 * lower(STRING) :: STRING -> toLower(STRING) :: STRING
 */
case object GQLAliasFunctionNameRewriter extends StepSequencer.Step with ASTRewriterFactory {

  override def preConditions: Set[StepSequencer.Condition] = Set(!FunctionInvocationsResolved)

  override def postConditions: Set[Condition] = Set(GQLAliasFunctionNameRewritten)

  override def invalidatedConditions: Set[Condition] = Set.empty

  private val GQLFunctionAliases: Map[String, String] = Map(
    "char_length" -> "character_length",
    "upper" -> "toUpper",
    "lower" -> "toLower"
  )

  override def getRewriter(
    semanticState: SemanticState,
    parameterTypeMapping: Map[String, ParameterTypeInfo],
    cypherExceptionFactory: CypherExceptionFactory,
    anonymousVariableNameGenerator: AnonymousVariableNameGenerator,
    cancellationChecker: CancellationChecker
  ): Rewriter = instance

  val instance: Rewriter = bottomUp(Rewriter.lift {
    case f @ FunctionInvocation(FunctionName(namespace, name), _, _, _, _)
      if namespace.parts.isEmpty && GQLFunctionAliases.exists(gqlAlias => name.equalsIgnoreCase(gqlAlias._1)) =>
      f.copy(functionName = FunctionName(GQLFunctionAliases(name.toLowerCase))(f.position))(f.position)
  })
}