Initial draft of luajava package support.

src/main/java/lua/GlobalState.java

@@ -45,6 +45,7 @@ public class GlobalState {
 	public static LValue getGlobalsTable() {
 		LTable table = new LTable();
 		Builtin.addBuiltins( table );
+		LuaJava.addBuiltins( table );
 		table.m_hash.put(new LString("_G"), table);
 		return table;
 	}

src/main/java/lua/LuaJava.java

@@ -0,0 +1,125 @@
+/**
+ * 
+ */
+package lua;
+
+/** LuaJava-like bindings to Java scripting. 
+ * 
+ * TODO: coerce types on way in and out, pick method base on arg count ant types.
+ */
+import java.lang.reflect.Field;
+import java.lang.reflect.Method;
+
+import lua.value.LFunction;
+import lua.value.LString;
+import lua.value.LTable;
+import lua.value.LValue;
+
+final class LuaJava extends LFunction {
+
+	static void addBuiltins(LTable table) {
+		LTable luajava = new LTable();
+		for ( int i=0; i<NAMES.length; i++ )
+			luajava.m_hash.put( new LString( NAMES[i] ), new LuaJava(i) );
+		table.m_hash.put( new LString( "luajava" ), luajava );
+	}
+
+	private static final int NEWINSTANCE  = 0;
+	private static final int BINDCLASS    = 1;
+	private static final int NEW          = 2;
+	private static final int CREATEPROXY  = 3;
+	private static final int LOADLIB      = 4;
+	
+	private static final String[] NAMES = { "newInstance", "bindClass", "new", "createProxy", "loadLib" };
+	
+	private int id;
+	private LuaJava( int id ) {			
+		this.id = id;
+	}
+
+	public String toString() {
+		return "builtin."+NAMES[id];
+	}
+	
+	// perform a lua call
+	public void luaStackCall(StackState state, int base, int top, int nresults) {
+		switch ( id ) {
+		case NEWINSTANCE:
+			String className = state.stack[base+1].luaAsString();
+				try {
+					Class c = Class.forName(className);
+					Object o = c.newInstance();
+					state.stack[base] = new LInstance( o );
+					state.top = base+1;
+				} catch (Exception e) {
+					throw new RuntimeException(e);
+				}
+			break;
+		default:
+			luaUnsupportedOperation();
+		}
+		if (nresults >= 0)
+			state.adjustTop(base + nresults);
+	}
+	
+	static class LInstance extends LValue {
+		private Object instance;
+		public LInstance(Object o) {
+			this.instance = o;
+		}
+		public String luaAsString() {
+			return instance.toString();
+		}
+		public void luaGetTable(StackState state, int base, LValue table, LValue key) {
+			Class c = instance.getClass();
+			final String s = key.luaAsString();
+			try {
+				Field f = c.getField(s);
+				Object o = f.get(instance);
+				String v = String.valueOf(o);
+				state.stack[base] = new LString( v );
+				state.top = base + 1;
+			} catch (NoSuchFieldException nsfe) {
+				state.stack[base] = new LMethod(instance,s);
+				state.top = base + 1;
+			} catch (Exception e) {
+				throw new RuntimeException(e);
+			}
+		}
+		public void luaSetTable(StackState state, int base, LValue table, LValue key, LValue val) {
+			Class c = instance.getClass();
+			String s = key.luaAsString();
+			try {
+				Field f = c.getField(s);
+				String v = val.luaAsString();
+				f.set(instance,v);
+				state.top = base;
+			} catch (Exception e) {
+				throw new RuntimeException(e);
+			}
+		}
+		
+	}
+
+	private static final class LMethod extends LFunction {
+		private final Object instance;
+		private final String s;
+		private LMethod(Object instance, String s) {
+			this.instance = instance;
+			this.s = s;
+		}
+
+		public void luaStackCall(StackState state, int base, int top, int nresults) {
+			Class c = instance.getClass();
+			try {
+				Method m = c.getMethod(s,new Class[0]);
+				Object o = m.invoke(instance,new Object[0]);
+				String v = String.valueOf(o);
+				state.stack[base] = new LString( v );
+				state.top = base + 1;
+			} catch (Exception e) {
+				throw new RuntimeException(e);
+			}
+		}
+	}
+}