// only one multi-type argument per declaration for now
// also allows only one combo right now (File/S with newFile)
// example:
// sS loadTextFile(File/S file) { ... }
svoid tok_expandMultiTypeArgument(LS tok,
  int iArgStart, int iArgEnd, // start and end of argument
  S argName, S mainType, S altType, S conversionExpr) {
  
  iArgEnd |= 1;

  int iOpening = lastIndexOf(tok, iArgStart, "("); // TODO: brackets
  int iClosing = findEndOfBracketPart2(tok, iOpening)-1;
  
  // function name
  int iName = iOpening-2;
  S name = assertIdentifier(get(tok, iName));
  
  int iType = tok_leftScanType(tok, iName);
  int iStart = tok_leftScanTypeArgsOpt(tok, iType);
  iStart = leftScanModifiers(tok, iStart);
  //print("Found method head: " + joinSubList(tok, iStart, iClosing+1));
  LS _args1 = subList(tok, iOpening+1, iArgStart);
  LS _args2 = subList(tok, iArgEnd&~1, iClosing);
  LS args1 = tok_parseArgsDeclList2(_args1);
  LS args2 = tok_parseArgsDeclList2(_args2);
  LS type = subList(tok, iType-1, iName);
  bool isVoid = containsOneOf(codeTokens(type), javaxVoidAliases());
  //printVars(+expr, +_args1, +_args2, +args1, +args2, +type, +isVoid);
  
  S altHead = joinSubList(tok, iStart, iOpening+1)
    + joinWithComma(concatLists(
        args1,
        ll(altType + " " + argName),
        args2)) + ")";
        
  if (tok_isSingleIdentifier(conversionExpr))
    conversionExpr += "(\*argName*/)";
        
  replaceTokens_reTok(tok, iArgStart|1, iArgEnd, mainType + " " + argName);
  tokPrepend_reTok(tok, iStart, altHead + " { "
    + (isVoid ? "" : "return ") + name + "(" + 
      joinWithComma(concatLists(
        map tok_lastIdentifier(args1),
        ll(conversionExpr),
        map tok_lastIdentifier(args2))) + "); }\n");
}

Began life as a copy of #1031905