/*
 * Copyright 2009-2010 Yuichiro Moriguchi
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package net.morilib.lisp.automata;

import net.morilib.lisp.ConsIterator;
import net.morilib.lisp.Datum;
import net.morilib.lisp.Environment;
import net.morilib.lisp.LispCharacter;
import net.morilib.lisp.LispMessage;
import net.morilib.lisp.LispString;
import net.morilib.lisp.Subr;
import net.morilib.lisp.subr.SubrUtils;

/**
 *
 *
 * @author MORIGUCHI, Yuichiro 2012/12/30
 */
public class TransitS extends Subr {

	/* (non-Javadoc)
	 * @see net.morilib.lisp.Subr#eval(net.morilib.lisp.Datum, net.morilib.lisp.Environment, net.morilib.lisp.LispMessage)
	 */
	@Override
	public Datum eval(Datum body, Environment env, LispMessage mesg) {
		ILispConfiguration f;
		ConsIterator itr = new ConsIterator(body);
		Datum c1a = SubrUtils.nextIf(itr, mesg, body), d;
		String s;

		if(!(c1a instanceof ILispConfiguration)) {
			throw mesg.getError("err.automata.require.state.dfa", c1a);
		} else {
			f = (ILispConfiguration)c1a;
			while(itr.hasNext()) {
				d = itr.next();
				if(d instanceof LispCharacter) {
					f = f.goSideEffect(d.getCharacterCodePoint(),
							mesg);
				} else if(d instanceof LispString) {
					s = d.getString();
					for(int i = 0; i < s.length(); i++) {
						f = f.goSideEffect(s.charAt(i), mesg);
					}
				} else {
					f = f.goSideEffect(d, mesg);
				}
			}
			SubrUtils.checkTerminated(itr, body, mesg);
			return (Datum)f;
		}
	}

}
