#!/usr/bin/perl

use strict;
use warnings;

use Benchmark;

our $verbosity = 7;
our $volume    = 1;
our $holy_crap = "Hmmmm.. here's the problem!";

timethese(10000000, {
     'Name1' => ' v_print0( 1, "Holy Crap = holy_crap\n"); ',
     'Name2' => ' v_print0( 1, "Holy Crap = $holy_crap\n"); ',
     'Name3' => ' v_print1( 1, sub { "Holy Crap = holy_crap\n"  } ); ',
     'Name4' => ' v_print1( 1, sub { "Holy Crap = $holy_crap\n" } ); ',
     'Name5' => ' v_print2( 1, \'"Holy Crap = holy_crap\n"\'  ); ',
     'Name6' => ' v_print2( 1, \'"Holy Crap = $holy_crap\n"\' ); ',
     'Name7' => ' if ( $volume >= $verbosity ) { v_print3( "Holy Crap  $holy_crap\n" ) }; ',
});

##</code><code>##

sub v_print0 {
    my $volume  = shift;
    my $message = shift;
    if ( $volume >= $verbosity ) {
        print $message;
    }
}

sub v_print1 {
    my $volume = shift;
    my $code   = shift;
    if ( $volume >= $verbosity ) {
        print &$code;
    }
}

sub v_print2 {
    my $volume = shift;
    my $code   = shift;
    if ( $volume >= $verbosity ) {
        print eval( $code );
    }
}

sub v_print3 {
    my $message = shift;
    print $message;
}

##</code><code>##

Benchmark: timing 10000000 iterations of Name1, Name2, Name3, Name4, Name5, Name6, Name7...
     Name1: 12 wallclock secs (11.24 usr +  0.01 sys = 11.25 CPU) @ 888888.89/s (n=10000000)
     Name2: 16 wallclock secs (16.08 usr +  0.00 sys = 16.08 CPU) @ 621890.55/s (n=10000000)
     Name3: 14 wallclock secs (13.93 usr + -0.01 sys = 13.92 CPU) @ 718390.80/s (n=10000000)
     Name4: 13 wallclock secs (14.10 usr +  0.00 sys = 14.10 CPU) @ 709219.86/s (n=10000000)
     Name5: 11 wallclock secs (11.26 usr +  0.00 sys = 11.26 CPU) @ 888099.47/s (n=10000000)
     Name6: 12 wallclock secs (11.00 usr +  0.01 sys = 11.01 CPU) @ 908265.21/s (n=10000000)
     Name7:  1 wallclock secs ( 1.24 usr +  0.00 sys =  1.24 CPU) @ 8064516.13/s (n=10000000)