#!/usr/local/bin/perl -w

use Benchmark;

my (@words, $count);
open(TESTDATA, "perldoc -t perlfunc|") || die $!;

while(<TESTDATA>) { chomp; push @words, /(\S+)/g }

print @words . " words\n";

my $alpha = '[a-zA-Z]';
my $alnum = '[a-zA-Z0-9]';
my $qr    = qr/^$alpha$alnum+$/;

timethese(100, {
   '/^$alpha$alnum+$/ ' => \&testsub,
   '/^$alpha$alnum+$/o' => \&testsubo,
   '/$qr/             ' => \&testsubqr1,
   '$qr               ' => \&testsubqr2,
   '/$qr/o            ' => \&testsubqro,
});

sub testsub    { foreach (@words) { $count++ if(/^$alpha$alnum+$/);  } }

sub testsubo   { foreach (@words) { $count++ if(/^$alpha$alnum+$/o); } }

sub testsubqr1 { foreach (@words) { $count++ if(/$qr/);              } }

sub testsubqr2 { foreach (@words) { $count++ if($_ =~ $qr);          } }

sub testsubqro { foreach (@words) { $count++ if(/$qr/o);             } }

##</code><code>##

/^$alpha$alnum+$/ : 20 wallclock secs (20.41 usr +  0.00 sys = 20.41 CPU) @  4.90/s (n=100)
/^$alpha$alnum+$/o:  9 wallclock secs ( 8.34 usr +  0.00 sys =  8.34 CPU) @ 11.99/s (n=100)
/$qr/             :  9 wallclock secs ( 9.59 usr +  0.00 sys =  9.59 CPU) @ 10.43/s (n=100)
$qr               : 10 wallclock secs ( 9.94 usr +  0.00 sys =  9.94 CPU) @ 10.06/s (n=100)
/$qr/o            :  9 wallclock secs ( 8.34 usr +  0.01 sys =  8.35 CPU) @ 11.98/s (n=100)