tool/src/main/java/org/antlr/tool/RuleLabelScope.java

/*
 * [The "BSD license"]
 *  Copyright (c) 2010 Terence Parr
 *  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.tool;

import org.antlr.runtime.Token;

public class RuleLabelScope extends AttributeScope {
	/** Rules have a predefined set of attributes as well as
	 *  the return values.  'text' needs to be computed though so.
	 */
	public static AttributeScope predefinedRulePropertiesScope =
		new AttributeScope("RulePredefined",null) {{
			addAttribute("text", null);
			addAttribute("start", null);
			addAttribute("stop", null);
			addAttribute("tree", null);
			addAttribute("st", null);
			isPredefinedRuleScope = true;
		}};

	public static AttributeScope predefinedTreeRulePropertiesScope =
		new AttributeScope("RulePredefined",null) {{
			addAttribute("text", null);
			addAttribute("start", null); // note: no stop; not meaningful
			addAttribute("tree", null);
			addAttribute("st", null);
			isPredefinedRuleScope = true;
		}};

	public static AttributeScope predefinedLexerRulePropertiesScope =
		new AttributeScope("LexerRulePredefined",null) {{
			addAttribute("text", null);
			addAttribute("type", null);
			addAttribute("line", null);
			addAttribute("index", null);
			addAttribute("pos", null);
			addAttribute("channel", null);
			addAttribute("start", null);
			addAttribute("stop", null);
			addAttribute("int", null);
			isPredefinedLexerRuleScope = true;
		}};

	public static AttributeScope[] grammarTypeToRulePropertiesScope =
		{
			null,
			predefinedLexerRulePropertiesScope,	// LEXER
			predefinedRulePropertiesScope,		// PARSER
			predefinedTreeRulePropertiesScope,	// TREE_PARSER
			predefinedRulePropertiesScope,		// COMBINED
		};

	public Rule referencedRule;

	public RuleLabelScope(Rule referencedRule, Token actionToken) {
		super("ref_"+referencedRule.name,actionToken);
		this.referencedRule = referencedRule;
	}

	/** If you label a rule reference, you can access that rule's
	 *  return values as well as any predefined attributes.
	 */
	public Attribute getAttribute(String name) {
		AttributeScope rulePropertiesScope =
			RuleLabelScope.grammarTypeToRulePropertiesScope[grammar.type];
		if ( rulePropertiesScope.getAttribute(name)!=null ) {
			return rulePropertiesScope.getAttribute(name);
		}

		if ( referencedRule.returnScope!=null ) {
			return referencedRule.returnScope.getAttribute(name);
		}
		return null;
	}
}