rttype
#define ttype(o) (rttype(o) & 0x3F)
#define ttypenv(o) (novariant(rttype(o)))
#define checktag(o,t) (rttype(o) == (t))
#define ttisclosure(o) ((rttype(o) & 0x1F) == LUA_TFUNCTION)
#define ttisequal(o1,o2) (rttype(o1) == rttype(o2))
#define iscollectable(o) (rttype(o) & BIT_ISCOLLECTABLE)