/*

  swap method o.add(a, b) to {

    ret super + " (added)";

  }

  or: swap method o.add(a, b) {

    ret super + " (added)";

  }

  =>

    var add_old = cc.add;

    o.add = (a, b) -> {

      ret o.add_fallback(add_old, a, b) + " (added)";

    };

*/

svoid tok_swapFunctions(LS tok) {

  int i;

  while ((i = jfind(tok, "swap method <id>.<id>(")) >= 0) {

    S obj = tok.get(i+4);

    S methodName = tok.get(i+8);

    int iOpening = i+10;

    int iClosing = indexOf(tok, i, ")");

    S args = joinSubList(tok, iOpening+2, iClosing-1);

    int iOpeningCurly = iClosing+2;

    if (eqGet(tok, iOpeningCurly, "to")) iOpeningCurly += 2;

    assertEquals(get(tok, iOpeningCurly), "{");

    int iClosingCurly = tok_findEndOfBlock(tok, iOpeningCurly)-1;

    S add_old = makeVar();

    LS tokBody = cloneList(cncSubList(tok, iOpeningCurly+1, iClosingCurly));

    bool needsSuper = jreplace_dyn(tokBody, "super",

      (_tok, nIdx) -> !eqGet(_tok, nIdx+3, "."),

      -> "\*obj*/.\*methodName*/_fallback(\*add_old*/, \*args*/)");

    S assignment =

        "\*obj*/.\*methodName*/ = (\*args*/) -> { " + join(tokBody) + "};";

    S src = needsSuper ?

      "{ var \*add_old*/ = \*obj*/.\*methodName*/; \n"

        + assignment + "\n}"

      : assignment;

    replaceTokens_reTok(tok, i, iClosingCurly+1, src);

  }

}