Thanks very much. Error looks useful for error handling... I think that's a secondary concern for me, though.

The big issue, I think (I'm still working on understanding what the crux of the problem is myself), is how to go back to a previous step.

For instance, if my program proceeds like this:

## Step 1
go_to_web_page_A();

## Step 2
look_for_stuff_on_web_page_A();

## Step 3
submit_form_on_A_to_go_to_B();
[download]

and it dies on step 2, that's almost always because step 1 failed. That is, it can't find the stuff it's looking for because the web page failed to load correctly.

So what I want to do is catch the failure of look_for_stuff_on_web_page_A() and, in case of a failure, retry go_to_web_page_A(); and then look_for_stuff_on_web_page_A(); a couple times before finally giving up.

Basically what it's doing is "Do A; Do B; If B fails, go back and do A again and then retry B;", and the part I'm having trouble with is the "If B fails, go back to A" part.

Any thoughts?

Error provides you a generic and extensible framework to handle errors, but it won't do exactly what you're looking for.

You basically need a method of retrying, which can be handled as BrowserUk states, or, based upon your code - can be something like:

  # CODE NOT TESTED 
  # for display purposes only 
  # void in Utah

  my $rc = undef;
  my $i = 0;
  do {
    $rc = go_to_web_page();
  } 
  while ( !$rc && $i++ < 3 );
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or, perhaps, using Error

  # CODE NOT TESTED 
  # for display purposes only 
  # void in Utah

  my $i = 0;

  GET_PAGE:
  while ( $i < 3 ) {
    try {
      go_to_web_page();
      # the above has to throw some kind of error 
      # for this to work
      last GET_PAGE;
    } 
    catch Error with {
      $i++;
    };
  }
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I'm sure there's a cleaner way to do that, but it's just an example off the top of my head (proof of concept).
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It's sad that a family can be torn apart by such a such a simple thing as a pack of wild dogs

Thanks very much. I like your examples -- I think my problem is that I haven't actually encapsulated each step of the program in a neat way. The necessary values for each step and the side effects each step produces are all entwined with each other.

So I guess I need to do some work on the general structure of the program.

Thanks for your help!