in reply to Time until event

You may want to consider changing the following. It's shorter, and it's probably how I would have written the loop. I realize life is not one big Perl-golf challenge, but in this case I prefer the shorter version. 
while ($time > 0) {
  print " " . ' ' x (3 - length($time)) . "$time $line";
  foreach (1..$backcount){print "\b"}
  $time -= 1;
  sleep 1;
}

[download]
to 
while ($time--) {
  printf(" %3s %s", $time, $line);

  print "\b" for (1..$backcount);
  # or this could even be written as:
  # print "\b" x $backcount;

  sleep 1;
}

[download]
No need to do the formatting of the time yourself, sprintf or printf can do it for you. The %3s part means format the string $time, right-justified within a column of 3 characters (space-padded if necessary). You could also do %3d as part of your printf format to do the same thing with zero-padding instead. See the perldoc page for printf for more fun options.

Having said that, I haven't actually executed your code, but I wonder if printing out backspaces isn't the most efficient way to erase the line. I don't have any other suggestions though, so I may be off base. Anyway, good job in saving/replacing $| within your sub. Returning globals to their previous values can save a lot of headaches.

blokhead

Replies are listed 'Best First'.
Re: Re: Time until event
by petral (Curate) on Sep 19, 2002 at 21:56 UTC
      "I wonder if printing out backspaces isn't the most efficient way to erase the line."

    Actually, "\r" serves that purpose, unless you are overprinting in mid-line.   But even then, simply reprinting the unchanging beginning of the line still seems simplest.
    eg, 
    printf(" %3d %s\r", $time, $line);

while(--$time) {
  sleep 1;
  printf(" %3d\r", $time);
}
print"\n";

    [download]
    See this whirligig for a similar function.

      p
[reply]
[d/l]

In Section Cool Uses for Perl