luai_numeq
if (luai_numeq(cast_num(k), n))
if (ttisnumber(gkey(n)) && luai_numeq(nvalue(gkey(n)), nk))
if (luai_numeq(cast_num(k), n)) /* index is int? */
#define luai_numisnan(L,a) (!luai_numeq((a), (a)))
case LUA_TNUMBER: return luai_numeq(nvalue(t1), nvalue(t2));