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Core Calcite APIs and engine.
There is a newer version: 1.17.0-flink-r3
/*
 * 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.
 */

/**
 * Provides a language for representing row-expressions.
 *
 * Life-cycle
 *
 * A {@link org.apache.calcite.sql2rel.SqlToRelConverter} converts a SQL
 * parse tree consisting of {@link org.apache.calcite.sql.SqlNode} objects into
 * a relational expression ({@link org.apache.calcite.rel.RelNode}). Several
 * kinds of nodes in this tree have row expressions
 * ({@link org.apache.calcite.rex.RexNode}).
 *
 * After the relational expression has been optimized, a
 * {@link org.apache.calcite.adapter.enumerable.JavaRelImplementor} converts it
 * into to a plan. If the plan is a Java parse tree, row-expressions are
 * translated into equivalent Java expressions.
 *
 * Expressions
 *
 *
 * Every row-expression has a type. (Compare with
 * {@link org.apache.calcite.sql.SqlNode}, which is created before validation,
 * and therefore types may not be available.)
 *
 * Every node in the parse tree is a {@link org.apache.calcite.rex.RexNode}.
 *     Sub-types are:
 * 
 *     {@link org.apache.calcite.rex.RexLiteral} represents a boolean,
 *         numeric, string, or date constant, or the value NULL.
 *     
 *     {@link org.apache.calcite.rex.RexVariable} represents a leaf of the
 *         tree. It has sub-types:
 *         
 *             {@link org.apache.calcite.rex.RexCorrelVariable} is a
 *                 correlating variable for nested-loop joins
 *             
 *             {@link org.apache.calcite.rex.RexInputRef} refers to a field
 *                 of an input relational expression
 *             
 *             {@link org.apache.calcite.rex.RexCall} is a call to an
 *                 operator or function.  By means of special operators, we can
 *                 use this construct to represent virtually every non-leaf node
 *                 in the tree.
 *             
 *             {@link org.apache.calcite.rex.RexRangeRef} refers to a
 *                 collection of contiguous fields from an input relational
 *                 expression. It usually exists only during translation.
 *             
 *         
 *     
 * 
 *
 * Expressions are generally
 *     created using a {@link org.apache.calcite.rex.RexBuilder} factory.
 *
 * Related packages
 * 
 *     {@link org.apache.calcite.sql} SQL object model
 *
 *     {@link org.apache.calcite.plan} Core classes, including
 * {@link org.apache.calcite.rel.type.RelDataType} and
 * {@link org.apache.calcite.rel.type.RelDataTypeFactory}.
 *
 * 
 */
@PackageMarker
package org.apache.calcite.rex;

import org.apache.calcite.avatica.util.PackageMarker;

// End package-info.java