Allow tables to be copied between threads

You can now pass in table objects as the parameters or return values for
a thread.  The contents of the table must themselves be objects that can
be passed into threads.  So (for instance), arbitrarily nested tables of
normal numbers and strings are fine.  But you still can't pass in a
function or a heavy userdata.

src/pre_generated-llthreads.nobj.c

@@ -921,6 +921,7 @@ static int llthread_move_values(lua_State *from_L, lua_State *to_L, int idx, int
 	size_t str_len;
 	int nvalues = 0;
 	int n;
+	int key, value;
 
 	for(n = idx; n <= top; n++) {
 		/* only support string/number/boolean/nil/lightuserdata. */
@@ -942,12 +943,26 @@ static int llthread_move_values(lua_State *from_L, lua_State *to_L, int idx, int
 			lua_pushlightuserdata(to_L, lua_touserdata(from_L, n));
 			break;
 		case LUA_TTABLE:
+			lua_newtable(to_L);
+			lua_pushnil(from_L);
+			while (lua_next(from_L, n) != 0) {
+				/* key is at -2, value at -1, but we need to normalize these
+				 * to positive indices */
+				key = lua_gettop(from_L) - 1;
+				value = lua_gettop(from_L);
+				llthread_move_values(from_L, to_L, key, value, is_arg);
+				/* Copied key and value are now at -2 and -1 in to_L. */
+				lua_settable(to_L, -3);
+				/* Pop value for next iteration */
+				lua_pop(from_L, 1);
+			}
+			break;
 		case LUA_TFUNCTION:
 		case LUA_TUSERDATA:
 		case LUA_TTHREAD:
 		default:
 			if (is_arg) {
-				return luaL_argerror(from_L, n, "table/function/userdata/thread types un-supported.");
+				return luaL_argerror(from_L, n, "function/userdata/thread types un-supported.");
 			} else {
 				/* convert un-supported types to an error string. */
 				lua_pushfstring(to_L, "Un-supported value: %s: %p",

src/thread.nobj.lua

@@ -228,6 +228,7 @@ static int llthread_move_values(lua_State *from_L, lua_State *to_L, int idx, int
 	size_t str_len;
 	int nvalues = 0;
 	int n;
+	int key, value;
 
 	for(n = idx; n <= top; n++) {
 		/* only support string/number/boolean/nil/lightuserdata. */
@@ -249,12 +250,26 @@ static int llthread_move_values(lua_State *from_L, lua_State *to_L, int idx, int
 			lua_pushlightuserdata(to_L, lua_touserdata(from_L, n));
 			break;
 		case LUA_TTABLE:
+			lua_newtable(to_L);
+			lua_pushnil(from_L);
+			while (lua_next(from_L, n) != 0) {
+				/* key is at -2, value at -1, but we need to normalize these
+				 * to positive indices */
+				key = lua_gettop(from_L) - 1;
+				value = lua_gettop(from_L);
+				llthread_move_values(from_L, to_L, key, value, is_arg);
+				/* Copied key and value are now at -2 and -1 in to_L. */
+				lua_settable(to_L, -3);
+				/* Pop value for next iteration */
+				lua_pop(from_L, 1);
+			}
+			break;
 		case LUA_TFUNCTION:
 		case LUA_TUSERDATA:
 		case LUA_TTHREAD:
 		default:
 			if (is_arg) {
-				return luaL_argerror(from_L, n, "table/function/userdata/thread types un-supported.");
+				return luaL_argerror(from_L, n, "function/userdata/thread types un-supported.");
 			} else {
 				/* convert un-supported types to an error string. */
 				lua_pushfstring(to_L, "Un-supported value: %s: %p",