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The ANTLR 4 grammar compiler.
There is a newer version: 4.13.2
/*
 * [The "BSD license"]
 *  Copyright (c) 2012 Terence Parr
 *  Copyright (c) 2012 Sam Harwell
 *  All rights reserved.
 *
 *  Redistribution and use in source and binary forms, with or without
 *  modification, are permitted provided that the following conditions
 *  are met:
 *
 *  1. Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *  2. Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *  3. The name of the author may not be used to endorse or promote products
 *     derived from this software without specific prior written permission.
 *
 *  THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 *  IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 *  OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 *  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 *  INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 *  NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 *  DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 *  THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 *  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 *  THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

package org.antlr.v4.tool.ast;

import org.antlr.runtime.Token;
import org.antlr.runtime.tree.Tree;
import org.antlr.v4.parse.ANTLRParser;
import org.antlr.v4.tool.Grammar;

public class RuleAST extends GrammarASTWithOptions {
	public RuleAST(RuleAST node) {
		super(node);
	}

	public RuleAST(Token t) { super(t); }
    public RuleAST(int type) { super(type); }

	public boolean isLexerRule() {
		String name = getRuleName();
		return name!=null && Grammar.isTokenName(name);
	}

	public String getRuleName() {
		GrammarAST nameNode = (GrammarAST)getChild(0);
		if ( nameNode!=null ) return nameNode.getText();
		return null;
	}

	@Override
	public RuleAST dupNode() { return new RuleAST(this); }

	public ActionAST getLexerAction() {
		Tree blk = getFirstChildWithType(ANTLRParser.BLOCK);
		if ( blk.getChildCount()==1 ) {
			Tree onlyAlt = blk.getChild(0);
			Tree lastChild = onlyAlt.getChild(onlyAlt.getChildCount()-1);
			if ( lastChild.getType()==ANTLRParser.ACTION ) {
				return (ActionAST)lastChild;
			}
		}
		return null;
	}

	@Override
	public Object visit(GrammarASTVisitor v) { return v.visit(this); }
}