consumeArgs(e, t) {
    if (t) {
      if (t.length !== e + 1)
        throw new G("The length of delimiters doesn't match the number of args!");
      for (var r = t[0], a = 0; a < r.length; a++) {
        var i = this.popToken();
        if (r[a] !== i.text)
          throw new G("Use of the macro doesn't match its definition", i);
      }
    }
    for (var l = [], s = 0; s < e; s++)
      l.push(this.consumeArg(t && t[s + 1]).tokens);
    return l;
  }
Expand the next token only once if possible.

If the token is expanded, the resulting tokens will be pushed onto
the stack in reverse order, and the number of such tokens will be
returned.  This number might be zero or positive.

If not, the return value is `false`, and the next token remains at the
top of the stack.

In either case, the next token will be on the top of the stack,
or the stack will be empty (in case of empty expansion
and no other tokens).

Used to implement `expandAfterFuture` and `expandNextToken`.

If expandableOnly, only expandable tokens are expanded and
an undefined control sequence results in an error.