Question: I've following jQuery code:

```
    $(function () {
      $(document).delegate('.products','click',function (e) {

        var table_id = $(this).closest('table').attr('id');
        var no = table_id.match(/\d+/)[0];            
        var first_row = $('#'+table_id).find('tbody tr:first').attr('id');
        var new_select = $('#'+first_row).children('td:first').find('select:first').clone();
        var tbody = $('#' + table_id + ' tbody');
        var n =  $(this).closest('table').find('select.prod_list').length+1;
        new_select.attr('id','product_id_'+no+'_'+n);
        new_select.attr('name', 'product_id_'+no+'['+n+']');

        $('#'+table_id).find('tbody tr:first').children('td:first').append(new_select);
        $('<button style="color:#C00; opacity: 2;margin-top: 6px;" type="button" class="close delete" data-dismiss="alert" aria-hidden="true">&times;</button>').appendTo( $(new_select.find('select')) );//Here I'm having an issue in placing the delete icon button
    });
  });

```

You can see that I'm trying to append a delete icon button to a newly added `<select>` but I'm not. Can some one please help me in this regard? The js Fiddle is: <http://jsfiddle.net/L247t/>

Answer: 
A common trick is to raise an exception with a `failwith "not implemented"` or just `assert false`. 

This will give you a warning if you have unused parameters in the unimplemented function. Although, they are disable by default. So you need to add -Wall option, to enable them.

Also, you can just add an intentionally unused variable in your implementation, like:

```
let reverse xs =
  let unimplemented = () in 
  xs

```
You might be interested by the [cppo pre-processor](http://mjambon.com/cppo-manual-0.9.2.txt) that describes itself as a `cpp` equivalent for OCaml programs and features a `#warning` directive. It seems to be available through `opam`.