ELambda.java

/***************************************************************************
   Copyright 2012 Emily Estes

   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.metanotion.simpletemplate.interpreter;


import java.util.Map;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import net.metanotion.functor.Block;
import net.metanotion.util.ChainedDictionary;
import net.metanotion.util.Dictionary;
import net.metanotion.util.MapDictionaryAdapter;
import net.metanotion.scripting.ObjectServer;

final class ELambda implements Element {
	private static final Logger logger = LoggerFactory.getLogger(ELambda.class);
	private final Element[] expr;
	public ELambda(Element[] expr) { this.expr = expr; }
	@Override public Object eval(final ObjectServer os, Object env0) {
		if(env0 instanceof Map) { env0 = new MapDictionaryAdapter((Map) env0); }
		final Object env = env0;
		return new Block<Object,Object>() {
			public Object eval(Object obj) throws Exception {
				if(obj instanceof Map) { obj = new MapDictionaryAdapter((Map) obj); }
				if(env instanceof Dictionary) {
					if(obj instanceof LEnv) {
						obj = new ChainedDictionary(new MapDictionaryAdapter(((LEnv) obj).map),
									new ChainedDictionary((Dictionary<String,Object>) env, ((LEnv) obj).parent));
					} else if(obj instanceof Dictionary) {
						obj = new ChainedDictionary((Dictionary<String,Object>) obj, (Dictionary<String,Object>) env);
					}
				}
				Object result = null;
				for(Element e: expr) { result = e.eval(os, obj); }
				return result;
			}
		};
	}
}