error handling in erlang.erl

function return_errors(DoError) ->
  case DoError of
    true ->
      {error, true};
    false ->
      ok
  end
.

%% this function will always throw an exception 
%% because I didn't handle the error return: {error, true}
function process_errors_badly() ->
  case return_errors(true) of
    ok ->
      io:format("It worked!!", []);
    err ->
      io:format("Why don't I ever execute?", []);
  end
.

%% because I did handle the error case 
%% this code executes without an exception
process_error_correctly() ->
  case return_errors(true) of
    ok ->
      io:format("It worked!!", []);
    {error, true} ->
      io:format("Yay I caught the error", []);
  end

.

Example of Bad Error handling in Perl.pl

sub return_errors() {
  my $do_error = shift;
  if ($do_error) {
     return {error => 1};
  }
  return {error => 0};
}

my $is_error = return_errors(1);

# I'm not correctly handling the error so this will never execute.
# Don't worry though something else somewhere seemingly completely
# unrelated will fail so I'll find out after a week of debugging.
if ($is_error->{err}) {
  die "there is an error!!!";
}


die "Oh no how did I get here?";