lua_rawset[-2, +0, m] void lua_rawset (lua_State *L, int index); Similar to lua_settable, but does a raw assignment (i.e., without metamethods).

lua_setmetatable[-1, +0, –] void lua_setmetatable (lua_State *L, int index); Pops a table from the stack and sets it as the new metatable for the value at the given index.

luaL_argcheck[-0, +0, v] void luaL_argcheck (lua_State *L, int cond, int arg, const char *extramsg); Checks whether cond is true. If it is not, raises an error with a standard message (see luaL_argerror).

debug.setupvalue (f, up, value) This function assigns the value value to the upvalue with index up of the function f. The function returns nil if there is no upvalue with the given index. Otherwise, it returns the name of the upvalue.

os.rename (oldname, newname) Renames the file or directory named oldname to newname. If this function fails, it returns nil, plus a string describing the error and the error code. Otherwise, it returns true.

string.reverse (s)s

math.log (x [, base]) Returns the logarithm of x in the given base. The default for base is e (so that the function returns the natural logarithm of x).

luaL_addchar[-?, +?, m] void luaL_addchar (luaL_Buffer *B, char c); Adds the byte c to the buffer B (see luaL_Buffer).

luaL_setmetatable[-0, +0, –] void luaL_setmetatable (lua_State *L, const char *tname); Sets the metatable of the object at the top of the stack as the metatable associated with name tname in the registry (see luaL_newmetatable).

math.tan (x) Returns the tangent of x (assumed to be in radians).