Function resume

third-party/lua-5.5.0/src/ldo.c:916–944

** Do the work for 'lua_resume' in protected mode. Most of the work ** depends on the status of the coroutine: initial state, suspended ** inside a hook, or regularly suspended (optionally with a continuation ** function), plus erroneous cases: non-suspended coroutine or dead ** coroutine. */

** coroutine.
*/
static void resume (lua_State *L, void *ud) {
  int n = *(cast(int*, ud));  /* number of arguments */
  StkId firstArg = L->top.p - n;  /* first argument */
  CallInfo *ci = L->ci;
  if (L->status == LUA_OK)  /* starting a coroutine? */
    ccall(L, firstArg - 1, LUA_MULTRET, 0);  /* just call its body */
  else {  /* resuming from previous yield */
    lua_assert(L->status == LUA_YIELD);
    L->status = LUA_OK;  /* mark that it is running (again) */
    if (isLua(ci)) {  /* yielded inside a hook? */
      /* undo increment made by 'luaG_traceexec': instruction was not
         executed yet */
      lua_assert(ci->callstatus & CIST_HOOKYIELD);
      ci->u.l.savedpc--;
      L->top.p = firstArg;  /* discard arguments */
      luaV_execute(L, ci);  /* just continue running Lua code */
    }
    else {  /* 'common' yield */
      if (ci->u.c.k != NULL) {  /* does it have a continuation function? */
        lua_unlock(L);
        n = (*ci->u.c.k)(L, LUA_YIELD, ci->u.c.ctx); /* call continuation */
        lua_lock(L);
        api_checknelems(L, n);
      }
      luaD_poscall(L, ci, n);  /* finish 'luaD_call' */
    }
    unroll(L, NULL);  /* run continuation */
  }
}


/*