DropCmd.java

package ppg.cmds;

import java.util.*;
import ppg.atoms.*;
import ppg.util.*;
public class DropCmd implements Command
{
	private Production prod; // productions to be dropped for some nonterminal
	private Vector sym; // or, the single nonterminal to be dropped
	
	/*
	public DropCmd(String symbol)
	{
		// here it does not matter whether it's a nonterminal or terminal
		sym = symbol;
		prod = null;
	}
	*/
	
	public DropCmd(Vector symbols)
	{
		sym = symbols;
		prod = null;
	}
	
	public DropCmd(Production productions)
	{
		prod = productions;
		sym = null;
	}

	public boolean isProdDrop() { return prod != null; }
	public boolean isSymbolDrop() { return sym != null; }
	
	public Production getProduction() { return prod; }
	public Vector getSymbols() { return sym; }
	
	public void unparse(CodeWriter cw) {
		//cw.begin(0);
		cw.write("DropCmd");
		cw.allowBreak(0);
		if (prod != null)
			prod.unparse(cw);
		else
			for (int i=0; i < sym.size(); i++) {
				cw.write((String)sym.elementAt(i));
			}
		//cw.end();
	}
	
}