#! /usr/bin/perl -w

use strict;
use POSIX;
use Benchmark;

sub via_anonsub {
  sub { sprintf '%04d%02d%02d%02d%02d%02d%05d',
    $_[5]+1900, $_[4]+1, $_[3], $_[2], $_[1], $_[0], $$
  }->(localtime())
}

sub via_sprintf {
  my @time = localtime();
  sprintf '%04d%02d%02d%02d%02d%02d%05d',
    $time[5]+1900, $time[4]+1, $time[3], $time[2], $time[1], $time[0], $$
}

sub via_concat {
  my @time = localtime();
  $time[4]++;
  $time[5]+=1900;
  $time[$_] = $time[$_]<10? "0".$time[$_]:$time[$_] for (0..5);
  my $filename = $time[5].$time[4].$time[3].$time[2].$time[1].$time[0].$$
}

sub via_posix {
  strftime( "%Y%m%d%H%M%S$$", localtime() )
}

print <<"PROOF";
via_concat:  ${\via_concat()}
via_anonsub: ${\via_anonsub()}
via_posix:   ${\via_posix()}
via_sprintf: ${\via_sprintf()}
PROOF

timethese( shift || 10000, {
  'via_anonsub' => \&via_anonsub,
  'via_concat'  => \&via_concat,
  'via_posix'   => \&via_posix,
  'via_sprintf' => \&via_sprintf,
});