Function funcargs

third-party/lua-5.3.5/src/lparser.c:817–859

static void funcargs (LexState *ls, expdesc *f, int line) {
  FuncState *fs = ls->fs;
  expdesc args;
  int base, nparams;
  switch (ls->t.token) {
    case '(': {  /* funcargs -> '(' [ explist ] ')' */
      luaX_next(ls);
      if (ls->t.token == ')')  /* arg list is empty? */
        args.k = VVOID;
      else {
        explist(ls, &args);
        luaK_setmultret(fs, &args);
      }
      check_match(ls, ')', '(', line);
      break;
    }
    case '{': {  /* funcargs -> constructor */
      constructor(ls, &args);
      break;
    }
    case TK_STRING: {  /* funcargs -> STRING */
      codestring(ls, &args, ls->t.seminfo.ts);
      luaX_next(ls);  /* must use 'seminfo' before 'next' */
      break;
    }
    default: {
      luaX_syntaxerror(ls, "function arguments expected");
    }
  }
  lua_assert(f->k == VNONRELOC);
  base = f->u.info;  /* base register for call */
  if (hasmultret(args.k))
    nparams = LUA_MULTRET;  /* open call */
  else {
    if (args.k != VVOID)
      luaK_exp2nextreg(fs, &args);  /* close last argument */
    nparams = fs->freereg - (base+1);
  }
  init_exp(f, VCALL, luaK_codeABC(fs, OP_CALL, base, nparams+1, 2));
  luaK_fixline(fs, line);
  fs->freereg = base+1;  /* call remove function and arguments and leaves
                            (unless changed) one result */
}