added EObjectIterator and made ECons Iterable

src/main/java/erjang/ECons.java

@@ -21,14 +21,15 @@
 import java.io.ByteArrayOutputStream;
 import java.nio.ByteBuffer;
 import java.io.IOException;
+import java.util.Iterator;
 import java.util.List;
 import java.util.Set;
 
 import erjang.m.ets.EMatchContext;
 import erjang.m.ets.EPattern;
 import erjang.m.ets.ETermPattern;
 
-public abstract class ECons extends EObject {
+public abstract class ECons extends EObject implements Iterable<EObject> {
 
 	@Override
 	int cmp_order() {
@@ -241,4 +242,8 @@ public void collectCharList(CharCollector out)
 		} else tail.collectCharList(out);
 	}
 
+	@Override
+	public Iterator<EObject> iterator() {
+		return new EObjectIterator(this);
+	}
 }

src/main/java/erjang/EObjectIterator.java

@@ -0,0 +1,58 @@
+package erjang;
+
+import java.util.Iterator;
+import java.util.NoSuchElementException;
+
+
+public class EObjectIterator implements Iterator<EObject> {
+	private EObject object = null;
+
+	public EObjectIterator(EObject object) {
+		this.object = object;
+	}
+
+	/* (non-Javadoc)
+	 * @see java.util.Iterator#hasNext()
+	 */
+	public boolean hasNext() {
+		if (object == null) {
+			return false;
+		}
+		return !object.isNil();
+	}
+
+	/* (non-Javadoc)
+	 * @see java.util.Iterator#next()
+	 */
+	public EObject next() {
+		if ((object == null)
+			|| object.isNil()) {
+			throw new NoSuchElementException();
+		}
+
+		EObject next;
+
+		ECons cons = object.testCons();
+		if ((cons != null)
+			// TODO how to handle EString? return each character? Or return it as single element only?
+			// for now we don't treat EString as collection, but as single element
+			&& !(cons instanceof EString)) {
+			next = cons.head();
+			object = cons.tail();
+		}
+		else {
+			// simple object, return it and set next object to null
+			next = object;
+			object = null;
+		}
+		return next;
+	}
+
+	/* (non-Javadoc)
+	 * @see java.util.Iterator#remove()
+	 */
+	public void remove() {
+		// not supported
+		throw new UnsupportedOperationException();
+	}
+}

src/test/java/erjang/EObjectIteratorTest.java

@@ -0,0 +1,190 @@
+package erjang;
+
+import java.util.Iterator;
+import java.util.NoSuchElementException;
+
+import junit.framework.TestCase;
+
+public class EObjectIteratorTest extends TestCase {
+	public void testNil() throws Exception {
+		Iterator<EObject> it = new EObjectIterator(ERT.NIL);
+		assertNotNull(it);
+		assertFalse(it.hasNext());
+	}
+
+	public void testNull() throws Exception {
+		Iterator<EObject> it = new EObjectIterator(null);
+		assertNotNull(it);
+		assertFalse(it.hasNext());
+	}
+
+	public void testEString() throws Exception {
+		EString message = EString.fromString("Hello, World!");
+		Iterator<EObject> it = new EObjectIterator(message);
+		assertNotNull(it);
+		assertTrue(it.hasNext());
+		EObject o = it.next();
+		assertNotNull(o);
+		assertEquals(message, o);
+		assertFalse(it.hasNext());
+		try {
+			it.next();
+			fail("no more elements, iterator should throw exception");
+		}
+		catch (NoSuchElementException t) {
+			// expected
+		}
+	}
+
+	public void testEInt() throws Exception {
+		EInteger num = ESmall.make(42);
+		Iterator<EObject> it = new EObjectIterator(num);
+		assertNotNull(it);
+		assertTrue(it.hasNext());
+		EObject o = it.next();
+		assertNotNull(o);
+		assertEquals(num, o);
+		assertFalse(it.hasNext());
+		try {
+			it.next();
+			fail("no more elements, iterator should throw exception");
+		}
+		catch (NoSuchElementException t) {
+			// expected
+		}
+	}
+
+	public void testSeqWithSingleNil() throws Exception {
+		ESeq seq = ESeq.fromArray(new EObject[] {
+				ERT.NIL
+		});
+		assertEquals(1, seq.length());
+		Iterator<EObject> it = seq.iterator();
+		assertNotNull(it);
+		assertTrue(it.hasNext());
+		EObject o = it.next();
+		assertNotNull(o);
+		assertTrue(o.isNil());
+		assertEquals(ERT.NIL, o);
+		assertFalse(it.hasNext());
+		try {
+			it.next();
+			fail("no more elements, iterator should throw exception");
+		}
+		catch (NoSuchElementException t) {
+			// expected
+		}
+	}
+
+	public void testSeqWithTwoNils() throws Exception {
+		ESeq seq = ESeq.fromArray(new EObject[] {
+				ERT.NIL,
+				ERT.NIL
+		});
+		assertEquals(2, seq.length());
+		Iterator<EObject> it = seq.iterator();
+		assertNotNull(it);
+		assertTrue(it.hasNext());
+		EObject o = it.next();
+		assertNotNull(o);
+		assertTrue(o.isNil());
+		assertEquals(ERT.NIL, o);
+		assertTrue(it.hasNext());
+		o = it.next();
+		assertNotNull(o);
+		assertTrue(o.isNil());
+		assertEquals(ERT.NIL, o);
+		assertFalse(it.hasNext());
+		try {
+			it.next();
+			fail("no more elements, iterator should throw exception");
+		}
+		catch (NoSuchElementException t) {
+			// expected
+		}
+	}
+
+	public void testSeqWithSingleObject() throws Exception {
+		EObject first = EString.fromString("Hello");
+		ESeq seq = ESeq.fromArray(new EObject[] {
+				first
+		});
+		assertEquals(1, seq.length());
+		Iterator<EObject> it = seq.iterator();
+		assertNotNull(it);
+		assertTrue(it.hasNext());
+		EObject o = it.next();
+		assertNotNull(o);
+		assertEquals(first, o);
+		assertFalse(it.hasNext());
+		try {
+			it.next();
+			fail("no more elements, iterator should throw exception");
+		}
+		catch (NoSuchElementException t) {
+			// expected
+		}
+	}
+
+	public void testSeqWithTwoObjects() throws Exception {
+		EObject first = EString.fromString("Hello");
+		EObject second = EString.fromString("World");
+		ESeq seq = ESeq.fromArray(new EObject[] {
+				first,
+				second
+		});
+		assertEquals(2, seq.length());
+		Iterator<EObject> it = seq.iterator();
+		assertNotNull(it);
+		assertTrue(it.hasNext());
+		EObject o = it.next();
+		assertNotNull(o);
+		assertEquals(first, o);
+		assertTrue(it.hasNext());
+		o = it.next();
+		assertNotNull(o);
+		assertEquals(second, o);
+		assertFalse(it.hasNext());
+		try {
+			it.next();
+			fail("no more elements, iterator should throw exception");
+		}
+		catch (NoSuchElementException t) {
+			// expected
+		}
+	}
+
+	public void testSeqWithThreeObjects() throws Exception {
+		EObject first = EString.fromString("Hello");
+		EObject second = EString.fromString("World");
+		EObject third = ESmall.make(42);
+		ESeq seq = ESeq.fromArray(new EObject[] {
+				first,
+				second,
+				third
+		});
+		assertEquals(3, seq.length());
+		Iterator<EObject> it = seq.iterator();
+		assertNotNull(it);
+		assertTrue(it.hasNext());
+		EObject o = it.next();
+		assertNotNull(o);
+		assertEquals(first, o);
+		assertTrue(it.hasNext());
+		o = it.next();
+		assertNotNull(o);
+		assertEquals(second, o);
+		assertTrue(it.hasNext());
+		o = it.next();
+		assertNotNull(o);
+		assertEquals(third, o);
+		assertFalse(it.hasNext());
+		try {
+			it.next();
+			fail("no more elements, iterator should throw exception");
+		}
+		catch (NoSuchElementException t) {
+			// expected
+		}
+	}
+}