/*
 * SimpleUnlexer.java
 * Copyright (C) 2004-2006, Bjorn Bringert (bringert@cs.chalmers.se)
 * 
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 * 
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */
package se.chalmers.cs.gf.linearize.unlex;

import se.chalmers.cs.gf.linearize.gfvalue.*;
import se.chalmers.cs.gf.parse.Token;

import java.util.List;
import java.util.regex.Pattern;


/**
 *  An unlexer that has some heuristics for where to
 *  insert spaces.
 *  It does not transform any tokens.
 */
public class SimpleUnlexer extends BasicUnlexer {


	protected String format(Token before, Token t, Token after) {
		return t.getValue() + separator(t,after);
        }

	protected String separator(Token t, Token after) {
		if (after == null || noSpaceAfter(t.getValue()) 
		    || noSpaceBefore(after.getValue())) {
			return "";
		} else {
			return " ";
		}
	}

        private Pattern noSpaceAfterPatt = Pattern.compile("^[\\(\\-\\[]"); 
        private boolean noSpaceAfter(CharSequence s) {
                return noSpaceAfterPatt.matcher(s).find();
        }

        private Pattern noSpaceBeforePatt = Pattern.compile("^[\\.\\,\\?\\!\\)\\:\\;\\-\\]]"); 
        private boolean noSpaceBefore(CharSequence s) {
                return noSpaceBeforePatt.matcher(s).find();
        }

}