Coerce script engine eval() return values to Java.

README.html

@@ -847,6 +847,7 @@ Files are no longer hosted at LuaForge.
 <tr valign="top"><td>&nbsp;&nbsp;<b>3.0-beta1</b></td><td><ul>
 <li>Fix bug that didn't read package.path from environment.</li>
 <li>Fix pluggable scripting engine lookup, simplify implementation, and add unit tests.</li>
+<li>Coerce script engine eval() return values to Java.</li>
 
 </ul></td></tr>
 </table></td></tr></table>

src/jse/org/luaj/vm2/lib/jse/JavaArray.java

@@ -23,8 +23,10 @@ package org.luaj.vm2.lib.jse;
 
 import java.lang.reflect.Array;
 
+import org.luaj.vm2.LuaTable;
 import org.luaj.vm2.LuaUserdata;
 import org.luaj.vm2.LuaValue;
+import org.luaj.vm2.lib.OneArgFunction;
 
 /**
  * LuaValue that represents a Java instance of array type.
@@ -41,8 +43,19 @@ class JavaArray extends LuaUserdata {
 
 	static final LuaValue LENGTH = valueOf("length");
 	
+	static final LuaTable array_metatable;
+	static {
+		array_metatable = new LuaTable();
+		array_metatable.rawset(LuaValue.LEN, new OneArgFunction() {
+			public LuaValue call(LuaValue u) {
+				return LuaValue.valueOf(Array.getLength(((LuaUserdata)u).m_instance));
+			}
+		});
+	}
+	
 	JavaArray(Object instance) {
 		super(instance);
+		setmetatable(array_metatable);
 	}
 	
 	public LuaValue get(LuaValue key) {

src/jse/org/luaj/vm2/script/LuaScriptEngine.java

@@ -155,7 +155,7 @@ public class LuaScriptEngine extends AbstractScriptEngine implements ScriptEngin
 				}
 				f.initupvalue1(g);
 			}
-			return f.invoke(LuaValue.NONE);
+			return toJava(f.invoke(LuaValue.NONE));
 		}
 	}
 
@@ -215,6 +215,13 @@ public class LuaScriptEngine extends AbstractScriptEngine implements ScriptEngin
 				}
 			});
 		}
+	}
+	
+	static private LuaValue toLua(Object javaValue) {
+		return javaValue == null? LuaValue.NIL:
+			javaValue instanceof LuaValue? (LuaValue) javaValue:
+			CoerceJavaToLua.coerce(javaValue);
+	}
 
 	static private Object toJava(LuaValue luajValue) {
 		switch ( luajValue.type() ) {
@@ -228,10 +235,17 @@ public class LuaScriptEngine extends AbstractScriptEngine implements ScriptEngin
 		}
 	}
 
-		static private LuaValue toLua(Object javaValue) {
+	static private Object toJava(Varargs v) {
-			return javaValue == null? LuaValue.NIL:
+		final int n = v.narg();
-				javaValue instanceof LuaValue? (LuaValue) javaValue:
+		switch (n) {
-				CoerceJavaToLua.coerce(javaValue);
+		case 0: return null;
+		case 1: return toJava(v.arg1());
+		default:
+			Object[] o = new Object[n];
+			for (int i=0; i<n; ++i)
+				o[i] = toJava(v.arg(i+1));
+			return o;
 		}
 	}
+
 }

test/junit/org/luaj/vm2/script/ScriptEngineTests.java

@@ -21,6 +21,7 @@
  ******************************************************************************/
 package org.luaj.vm2.script;
 
+import java.io.ByteArrayInputStream;
 import java.io.CharArrayReader;
 import java.io.CharArrayWriter;
 import java.io.Reader;
@@ -133,12 +134,12 @@ public class ScriptEngineTests extends TestSuite  {
  				}
              });
             Object r = e.eval("return f('abc')");
-            assertEquals("abc123", r.toString());
+            assertEquals("abc123", r);
 		}
 		public void testCompiledScript() throws ScriptException {
             CompiledScript cs = ((Compilable)e).compile("y = math.sqrt(x); return y");
             b.put("x", 144);
-            assertEquals("12", cs.eval(b).toString());
+            assertEquals(12, cs.eval(b));
 		}
 		public void testBuggyLuaScript() {
 	        try {
@@ -186,31 +187,31 @@ public class ScriptEngineTests extends TestSuite  {
 		public void testBindingJavaInt() throws ScriptException {
 	        CompiledScript cs = ((Compilable)e).compile("y = x; return 'x '..type(x)..' '..tostring(x)\n");
 	        b.put("x", 111);
-	        assertEquals("x number 111", cs.eval(b).toString());
+	        assertEquals("x number 111", cs.eval(b));
 	        assertEquals(111, b.get("y"));
 		}
 		public void testBindingJavaDouble() throws ScriptException {
 	        CompiledScript cs = ((Compilable)e).compile("y = x; return 'x '..type(x)..' '..tostring(x)\n");
 	        b.put("x", 125.125);
-	        assertEquals("x number 125.125", cs.eval(b).toString());
+	        assertEquals("x number 125.125", cs.eval(b));
 	        assertEquals(125.125, b.get("y"));
 		}
 		public void testBindingJavaString() throws ScriptException {
 	        CompiledScript cs = ((Compilable)e).compile("y = x; return 'x '..type(x)..' '..tostring(x)\n");
 	        b.put("x", "foo");
-	        assertEquals("x string foo", cs.eval(b).toString());
+	        assertEquals("x string foo", cs.eval(b));
 	        assertEquals("foo", b.get("y"));
 		}
 		public void testBindingJavaObject() throws ScriptException {
 	        CompiledScript cs = ((Compilable)e).compile("y = x; return 'x '..type(x)..' '..tostring(x)\n");
 	        b.put("x", new SomeUserClass());
-	        assertEquals("x userdata some-user-value", cs.eval(b).toString());
+	        assertEquals("x userdata some-user-value", cs.eval(b));
 	        assertEquals(SomeUserClass.class, b.get("y").getClass());
 		}
 		public void testBindingJavaArray() throws ScriptException {
-	        CompiledScript cs = ((Compilable)e).compile("y = x; return 'x '..type(x)..' '..x[1]..' '..x[2]\n");
+	        CompiledScript cs = ((Compilable)e).compile("y = x; return 'x '..type(x)..' '..#x..' '..x[1]..' '..x[2]\n");
 	        b.put("x", new int[] { 777, 888 });
-	        assertEquals("x userdata 777 888", cs.eval(b).toString());
+	        assertEquals("x userdata 2 777 888", cs.eval(b));
 	        assertEquals(int[].class, b.get("y").getClass());
 		}
 		public void testBindingLuaFunction() throws ScriptException {
@@ -223,9 +224,18 @@ public class ScriptEngineTests extends TestSuite  {
 	        CompiledScript cs = ((Compilable)e).compile(
 	        		"x = x or luajava.newInstance('java.lang.String', 'test')\n" +
 	        		"return 'x ' ..  type(x) .. ' ' .. tostring(x)\n");
-	        assertEquals("x string test", cs.eval(b).toString());
+	        assertEquals("x string test", cs.eval(b));
 	        b.put("x", new SomeUserClass());
-	        assertEquals("x userdata some-user-value", cs.eval(b).toString());
+	        assertEquals("x userdata some-user-value", cs.eval(b));
+	    }	
+		public void testReturnMultipleValues() throws ScriptException {
+	        CompiledScript cs = ((Compilable)e).compile("return 'foo', 'bar'\n");
+	        Object o = cs.eval();
+	        assertEquals(Object[].class, o.getClass());
+	        Object[] array = (Object[]) o;
+	        assertEquals(2, array.length);
+	        assertEquals("foo", array[0]);
+	        assertEquals("bar", array[1]);
 		}
 	}