Duration(3) User Contributed Perl Documentation Duration(3)NAMETime::Duration - rounded or exact English expression of durations
SYNOPSIS
Example use in a program that ends by noting its runtime:
my $start_time = time();
use Time::Duration;
# then things that take all that time, and then ends:
print "Runtime ", duration(time() - $start_time), ".\n";
Example use in a program that reports age of a file:
use Time::Duration;
my $file = 'that_file';
my $age = $^T - (stat($file))[9]; # 9 = modtime
print "$file was modified ", ago($age);
DESCRIPTION
This module provides functions for expressing durations in rounded or
exact terms.
In the first example in the Synopsis, using
duration($interval_seconds):
If the "time() - $start_time" is 3 seconds, this prints "Runtime: 3
seconds.". If it's 0 seconds, it's "Runtime: 0 seconds.". If it's 1
second, it's "Runtime: 1 second.". If it's 125 seconds, you get
"Runtime: 2 minutes and 5 seconds.". If it's 3820 seconds (which is
exactly 1h, 3m, 40s), you get it rounded to fit within two expressed
units: "Runtime: 1 hour and 4 minutes.". Using duration_exact instead
would return "Runtime: 1 hour, 3 minutes, and 40 seconds".
In the second example in the Synopsis, using ago($interval_seconds):
If the $age is 3 seconds, this prints "file was modified 3 seconds
ago". If it's 0 seconds, it's "file was modified just now", as a
special case. If it's 1 second, it's "from 1 second ago". If it's 125
seconds, you get "file was modified 2 minutes and 5 seconds ago". If
it's 3820 seconds (which is exactly 1h, 3m, 40s), you get it rounded to
fit within two expressed units: "file was modified 1 hour and 4 minutes
ago". Using ago_exact instead would return "file was modified 1 hour,
3 minutes, and 40 seconds ago". And if the file's modtime is,
surprisingly, three seconds into the future, $age is -3, and you'll get
the equally and appropriately surprising "file was modified 3 seconds
from now."
FUNCTIONS
This module provides all the following functions, which are all
exported by default when you call "use Time::Duration;".
duration($seconds)
duration($seconds, $precision)
Returns English text expressing the approximate time duration of
abs($seconds), with at most "$precision || 2" expressed units.
(That is, duration($seconds) is the same as duration($seconds,2).)
For example, duration(120) or duration(-120) is "2 minutes". And
duration(0) is "0 seconds".
The precision figure means that no more than that many units will
be used in expressing the time duration. For example, 31,629,659
seconds is a duration of exactly 1 year, 1 day, 2 hours, and 59
seconds (assuming 1 year = exactly 365 days, as we do assume in
this module). However, if you wanted an approximation of this to
at most two expressed (i.e., nonzero) units, it would round it and
truncate it to "1 year and 1 day". Max of 3 expressed units would
get you "1 year, 1 day, and 2 hours". Max of 4 expressed units
would get you "1 year, 1 day, 2 hours, and 59 seconds", which
happens to be exactly true. Max of 5 (or more) expressed units
would get you the same, since there are only four nonzero units
possible in for that duration.
duration_exact($seconds)
Same as duration($seconds), except that the returned value is an
exact (unrounded) expression of $seconds. For example,
duration_exact(31629659) returns "1 year, 1 day, 2 hours, and 59
seconds later", which is exactly true.
ago($seconds)
ago($seconds, $precision)
For a positive value of seconds, this prints the same as
"duration($seconds, [$precision]) . ' ago'". For example, ago(120)
is "2 minutes ago". For a negative value of seconds, this prints
the same as "duration($seconds, [$precision]) . ' from now'". For
example, ago(-120) is "2 minutes from now". As a special case,
ago(0) returns "right now".
ago_exact($seconds)
Same as ago($seconds), except that the returned value is an exact
(unrounded) expression of $seconds.
from_now($seconds)
from_now($seconds, $precision)
from_now_exact($seconds)
The same as ago(-$seconds), ago(-$seconds, $precision),
ago_exact(-$seconds). For example, from_now(120) is "2 minutes
from now".
later($seconds)
later($seconds, $precision)
For a positive value of seconds, this prints the same as
"duration($seconds, [$precision]) . ' later'". For example,
ago(120) is "2 minutes later". For a negative value of seconds,
this prints the same as "duration($seconds, [$precision]) .
' earlier'". For example, later(-120) is "2 minutes earlier". As
a special case, later(0) returns "right then".
later_exact($seconds)
Same as later($seconds), except that the returned value is an exact
(unrounded) expression of $seconds.
earlier($seconds)
earlier($seconds, $precision)
earlier_exact($seconds)
The same as later(-$seconds), later(-$seconds, $precision),
later_exact(-$seconds). For example, earlier(120) is "2 minutes
earlier".
concise( function( ... ) )
Concise takes the string output of one of the above functions and
makes it more concise. For example, "ago(4567)" returns "1 hour
and 16 minutes ago", but "concise(ago(4567))" returns "1h16m ago".
I18N/L10N NOTES
Little of the internals of this module are English-specific. See
source and/or contact me if you're interested in making a localized
version for some other language than English.
BACKSTORY
I wrote the basic "ago()" function for use in Infobot
("http://www.infobot.org"), because I was tired of this sort of
response from the Purl Infobot:
me> Purl, seen Woozle?
<Purl> Woozle was last seen on #perl 20 days, 7 hours, 32 minutes
and 40 seconds ago, saying: Wuzzle!
I figured if it was 20 days ago, I don't care about the seconds. So
once I had written "ago()", I abstracted the code a bit and got all the
other functions.
CAVEAT
This module calls a durational "year" an interval of exactly 365 days
of exactly 24 hours each, with no provision for leap years or monkey
business with 23/25 hour days (much less leap seconds!). But since the
main work of this module is approximation, that shouldn't be a great
problem for most purposes.
SEE ALSO
Date::Interval, which is similarly named, but does something rather
different.
Star Trek: The Next Generation (1987-1994), where the character Data
would express time durations like "1 year, 20 days, 22 hours, 59
minutes, and 35 seconds" instead of rounding to "1 year and 21 days".
This is because no-one ever told him to use Time::Duration.
COPYRIGHT AND DISCLAIMER
Copyright 2006, Sean M. Burke "sburke@cpan.org", all rights reserved.
This program is free software; you can redistribute it and/or modify it
under the same terms as Perl itself.
This program is distributed in the hope that it will be useful, but
without any warranty; without even the implied warranty of
merchantability or fitness for a particular purpose.
AUTHOR
Current maintainer Avi Finkel, "avi@finkel.org"; Original author Sean
M. Burke, "sburke@cpan.org"
perl v5.14.1 2007-08-19 Duration(3)
