Better error messages for some polymorphic functions

New auxiliary functions/macros 'luaL_argexpected'/'luaL_typeerror'
ease the creation of error messages such as

  bad argument #2 to 'setmetatable' (nil or table expected, got boolean)

(The novelty being the "got boolean" part...)

1 files changed, 2 insertions, 2 deletions

diff --git a/lstrlib.c b/lstrlib.c
index a635e9d4..e9c60c0f 100644
--- a/lstrlib.c
+++ b/lstrlib.c
@@ -857,9 +857,9 @@ static int str_gsub (lua_State *L) {
   lua_Integer n = 0;  /* replacement count */
   MatchState ms;
   luaL_Buffer b;
-  luaL_argcheck(L, tr == LUA_TNUMBER || tr == LUA_TSTRING ||
+  luaL_argexpected(L, tr == LUA_TNUMBER || tr == LUA_TSTRING ||
                    tr == LUA_TFUNCTION || tr == LUA_TTABLE, 3,
-                      "string/function/table expected");
+                      "string/function/table");
   luaL_buffinit(L, &b);
   if (anchor) {
     p++; lp--;  /* skip anchor character */