comments

lua.c

@@ -1,5 +1,5 @@
 /*
-** $Id: lua.c,v 1.215 2014/10/17 16:28:21 roberto Exp roberto $
+** $Id: lua.c,v 1.216 2014/10/20 18:19:26 roberto Exp roberto $
 ** Lua stand-alone interpreter
 ** See Copyright Notice in lua.h
 */
@@ -158,7 +158,8 @@ static void l_message (const char *pname, const char *msg) {
 
 /*
 ** Check whether 'status' is not OK and, if so, prints the error
-** message on the top of the stack.
+** message on the top of the stack. It assumes that the error object
+** is a string, as it was either generated by Lua or by 'msghandler'.
 */
 static int report (lua_State *L, int status) {
   if (status != LUA_OK) {
@@ -176,15 +177,15 @@ static int report (lua_State *L, int status) {
 static int msghandler (lua_State *L) {
   const char *msg = lua_tostring(L, 1);
   if (msg == NULL) {  /* is error object not a string? */
-    if (luaL_callmeta(L, 1, "__tostring") &&  /* did have a metamethod */
-        lua_type(L, -1) == LUA_TSTRING)  /* and it produce a string? */
+    if (luaL_callmeta(L, 1, "__tostring") &&  /* does it have a metamethod */
+        lua_type(L, -1) == LUA_TSTRING)  /* that produces a string? */
       return 1;  /* that is the message */
     else
       msg = lua_pushfstring(L, "(error object is a %s value)",
                                luaL_typename(L, 1));
   }
   luaL_traceback(L, L, msg, 1);  /* append a standard traceback */
-  return 1;
+  return 1;  /* return the traceback */
 }