asterixdb/asterix-maven-plugins/asterix-grammar-extension-maven-plugin/src/test/resources/lang/extension.jj

/*
 * 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.
 */
// If you want to put an additional import, just add import statements like the following.
// import package name
import org.apache.asterix.lang.extension.EchoStatement;

// To remove an import, we use the keyword, unimport
// unimport package name

// If you want to add a method in the class definition (before PARSER_END), use the following phrase and attach
// new method right after the phrase.
// @new_at_the_end
@new_at_the_class_def
    public void initScope() {
            scopeStack.push(RootScopeFactory.createRootScope(this));
    }

// Merging of non-terminals can only be done on non-terminals which conform to the following structure.
// Content will simply be prepended or appended to the base blocks.
// Note: refrain from using the strings "before:" and "after:" in the merge areas as that will break the merge.
// As a workaround, you can always override
// one additional possible change is direct replacement and it can be done through the followin syntax:
// @merge replace "base phrase" with "extension phrase" true/false
// Here, true/false tells whether the tool needs to process the three blocks.
// If true, like normal @merge case, before and after clause in each block will be processed
// after "base phrase" in the blocks have been replaced with "new phrase".
// If false, then it just expects the blank form that consists of three blocks and not process them.
// Only, "base phrase" in the blocks will be replaced with "new phrase".
@merge
Statement SingleStatement() throws ParseException:
{
  // merge area 1
  before:
  after:
}
{
  (
    // merge area 2
    before:
    after:    | stmt = EchoStatement())
  {
    // merge area 3
  }
}

// In the following case, all instances of the first phrase inside of "" will be replaced with the second phrase in "".
// Also, we don't check "before:" and "after:" section of each area. That check will be ignored since
// the last parameter is set to false.
@merge replace "nameComponents = QualifiedName() (<AS> var = Variable())?" with "nameComponents   =   QualifiedName()  (<AS> var = Variable())? " false
InsertStatement InsertStatement() throws ParseException:
{
  // merge area 1
}
{
    (
    // merge area 2
    )
    {
      // merge area 3
    }
}


// The default
// Adding a new node. if a node exists, it will throw an exception.
@new
Statement EchoStatement() throws ParseException:
{
  String arg = null;
}
{
  <ECHO> arg = Identifier()
    {
      return new EchoStatement(arg);
    }
}

// Overriding a non-terminal. if exists in base, it will be overriden, otherwise, it will be added
// @override


// Terminals can be added like the following.
<DEFAULT,IN_DBL_BRACE>
TOKEN :
{
    <ECHO : "echo">
}

// If something needs to be added at the end of file, you can use @new_at_the_end like the following.
@new_at_the_end
<DEFAULT,IN_DBL_BRACE>
TOKEN :
{
    <METAVARIABLE : "$$" <IDENTIFIER> >
}