Function mainfunc

depends/lua/src/lparser.c:1613–1625

** compiles the main function, which is a regular vararg function with an ** upvalue named LUA_ENV */

** upvalue named LUA_ENV
*/
static void mainfunc (LexState *ls, FuncState *fs) {
  BlockCnt bl;
  expdesc v;
  open_func(ls, fs, &bl);
  fs->f->is_vararg = 1;  /* main function is always declared vararg */
  init_exp(&v, VLOCAL, 0);  /* create and... */
  newupvalue(fs, ls->envn, &v);  /* ...set environment upvalue */
  luaC_objbarrier(ls->L, fs->f, ls->envn);
  luaX_next(ls);  /* read first token */
  statlist(ls);  /* parse main body */
  check(ls, TK_EOS);
  close_func(ls);
}


LClosure *luaY_parser (lua_State *L, ZIO *z, Mbuffer *buff,