Improve calling convention handling when the number of arguments doesn't match the expected number, and the number of return values doesn't match those needed.

src/main/java/lua/Builtin.java

@@ -4,6 +4,7 @@
 package lua;
 
 import lua.value.LFunction;
+import lua.value.LNil;
 import lua.value.LString;
 import lua.value.LTable;
 import lua.value.LValue;
@@ -30,7 +31,7 @@ final class Builtin extends LFunction {
 	}
 	
 	// perform a lua call
-	public void luaStackCall(StackState state, int base, int nargs) {
+	public int luaStackCall(StackState state, int base, int nargs) {
 		switch ( id ) {
 		case PRINT:
 			for ( int i=0; i<nargs; i++ ) {
@@ -39,13 +40,14 @@ final class Builtin extends LFunction {
 				System.out.print( String.valueOf(state.stack[base+1+i]) );
 			}
 			System.out.println();
-			return;
+			return 0;
 		case PAIRS:
 			LValue value = state.stack[base+1].luaPairs();
 			state.stack[base] = value;
-			return;
+			return 1;
 		default:
 			luaUnsupportedOperation();
+			return 0;
 		}
 	}
 

src/main/java/lua/io/Closure.java

@@ -17,7 +17,8 @@ public class Closure extends LValue {
 
 
 	// perform a lua call
-	public void luaStackCall(StackState state, int base, int nresults) {
-		state.vmExecute( this, base+1 );
+	public int luaStackCall(StackState state, int base, int nargs) {
+		state.clear( base+1+nargs, p.numparams-nargs );
+		return state.vmExecute( this, base+1 );
 	}
 }

src/main/java/lua/value/LTable.java

@@ -50,15 +50,14 @@ public class LTable extends LValue {
 		}
 
 		// perform a lua call
-		public void luaStackCall(StackState state, int base, int nresults) {
+		public int luaStackCall(StackState state, int base, int nargs) {
 			if ( e.hasMoreElements() ) {
 				LValue key = (LValue) e.nextElement();
 				state.stack[base] = key;
 				state.stack[base+1] = t.luaGetTable(key);
-			} else {
-				state.stack[base] = LNil.NIL;
+				return 2;
 			}
-			
+			return 0;			
 		}
 	}
 

src/main/java/lua/value/LValue.java

@@ -14,9 +14,10 @@ public class LValue {
 		return true;
 	}
 
-	// perform a lua call
-	public void luaStackCall(StackState state, int base, int nargs) {
+	// perform a lua call, return number of results actually produced
+	public int luaStackCall(StackState state, int base, int nargs) {
 		luaUnsupportedOperation();
+		return 0;
 	}
 
 	// unsupported except for numbers