GrammarUnreachableAltsMessage.java example

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FURCAS-master
/*
 [The "BSD licence"]
 Copyright (c) 2005-2008 Terence Parr
 All rights reserved.

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 1. Redistributions of source code must retain the above copyright
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    documentation and/or other materials provided with the distribution.
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    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
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package org.antlr.tool;

import org.antlr.stringtemplate.StringTemplate;
import org.antlr.analysis.DecisionProbe;
import org.antlr.analysis.DFAState;
import org.antlr.analysis.NFAState;
import org.antlr.analysis.SemanticContext;
import antlr.Token;

import java.util.Iterator;
import java.util.List;
import java.util.Set;

/** Reports a potential parsing issue with a decision; the decision is
 *  nondeterministic in some way.
 */
public class GrammarUnreachableAltsMessage extends Message {
	public DecisionProbe probe;
    public List alts;

	public GrammarUnreachableAltsMessage(DecisionProbe probe,
										 List alts)
	{
		super(ErrorManager.MSG_UNREACHABLE_ALTS);
		this.probe = probe;
		this.alts = alts;
		// flip msg ID if alts are actually token refs in Tokens rule
		if ( probe.dfa.isTokensRuleDecision() ) {
			setMessageID(ErrorManager.MSG_UNREACHABLE_TOKENS);
		}
	}

	public String toString() {
		GrammarAST decisionASTNode = probe.dfa.getDecisionASTNode();
		line = decisionASTNode.getLine();
		column = decisionASTNode.getColumn();
		String fileName = probe.dfa.nfa.grammar.getFileName();
		if ( fileName!=null ) {
			file = fileName;
		}

		StringTemplate st = getMessageTemplate();

		if ( probe.dfa.isTokensRuleDecision() ) {
			// alts are token rules, convert to the names instead of numbers
			for (int i = 0; i < alts.size(); i++) {
				Integer altI = (Integer) alts.get(i);
				String tokenName =
					probe.getTokenNameForTokensRuleAlt(altI.intValue());
				// reset the line/col to the token definition
				NFAState ruleStart =
					probe.dfa.nfa.grammar.getRuleStartState(tokenName);
				line = ruleStart.associatedASTNode.getLine();
				column = ruleStart.associatedASTNode.getColumn();
				st.setAttribute("tokens", tokenName);
			}
		}
		else {
			// regular alt numbers, show the alts
			st.setAttribute("alts", alts);
		}

		return super.toString(st);
	}

}