/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.apache.spark.sql.catalyst

/**
 * Provides a logical query plan [[Analyzer]] and supporting classes for performing analysis.
 * Analysis consists of translating [[UnresolvedAttribute]]s and [[UnresolvedRelation]]s
 * into fully typed objects using information in a schema [[Catalog]].
 */
package object analysis {

  /**
   * Responsible for resolving which identifiers refer to the same entity.  For example, by using
   * case insensitive equality.
   */
  type Resolver = (String, String) => Boolean

  val caseInsensitiveResolution = (a: String, b: String) => a.equalsIgnoreCase(b)
  val caseSensitiveResolution = (a: String, b: String) => a == b
}
