/*
 * Copyright 2009 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.subr;

import net.morilib.lisp.Cons;
import net.morilib.lisp.Datum;
import net.morilib.lisp.Environment;
import net.morilib.lisp.LispMessage;
import net.morilib.lisp.Nil;
import net.morilib.lisp.Subr;

public abstract class UnaryArgs extends Subr {
	
	protected abstract Datum execute(
			Datum c1a, Environment env, LispMessage mesg);
	
	public Datum eval(
			Datum body,
			Environment env,
			LispMessage mesg) {
		if(body instanceof Cons) {
			Cons c1 = (Cons)body;
			Datum c1a = c1.getCar();
			
			if(c1.getCdr() != Nil.NIL) {
				//throw new LispException("wrong number of arguments");
				throw mesg.getError("err.argument", symbolName);
			}
			return execute(c1a, env, mesg);
		} else {
			//throw new LispException("wrong number of arguments");
			throw mesg.getError("err.argument", symbolName);
		}
	}

}
