Function addk

ThirdParty/lua/lua/lcode.c:312–336

** Use scanner's table to cache position of constants in constant list ** and try to reuse constants */

** and try to reuse constants
*/
static int addk (FuncState *fs, TValue *key, TValue *v) {
  lua_State *L = fs->ls->L;
  Proto *f = fs->f;
  TValue *idx = luaH_set(L, fs->ls->h, key);  /* index scanner table */
  int k, oldsize;
  if (ttisinteger(idx)) {  /* is there an index there? */
    k = cast_int(ivalue(idx));
    /* correct value? (warning: must distinguish floats from integers!) */
    if (k < fs->nk && ttype(&f->k[k]) == ttype(v) &&
                      luaV_rawequalobj(&f->k[k], v))
      return k;  /* reuse index */
  }
  /* constant not found; create a new entry */
  oldsize = f->sizek;
  k = fs->nk;
  /* numerical value does not need GC barrier;
     table has no metatable, so it does not need to invalidate cache */
  setivalue(idx, k);
  luaM_growvector(L, f->k, k, f->sizek, TValue, MAXARG_Ax, "constants");
  while (oldsize < f->sizek) setnilvalue(&f->k[oldsize++]);
  setobj(L, &f->k[k], v);
  fs->nk++;
  luaC_barrier(L, f, v);
  return k;
}


int luaK_stringK (FuncState *fs, TString *s) {