ch09.038_best

Perl Best Practices the source code

##############################################################################
##   Code fragment (Recommended) from Chapter 9 of "Perl Best Practices"    ##
##     Copyright (c) O'Reilly & Associates, 2005. All Rights Reserved.      ##
##  See: http://www.oreilly.com/pub/a/oreilly/ask_tim/2001/codepolicy.html  ##
##############################################################################


# Standard modules...
use strict;
use warnings;
use IO::Prompt;
use Carp;
use English qw( -no_match_vars );
use Data::Alias;
use Readonly;

Readonly my $SPACE => q{ };

Readonly my %PAD_DEFAULTS => (
    cols     => 78,
    centered => 0,
    filler   => $SPACE,
    # etc.
);
 
sub padded {
    my ($text, $arg_ref) = @_;
 
    # Unpack optional arguments and set defaults...
    my %arg = ref $arg_ref eq 'HASH' ? (%PAD_DEFAULTS, %{$arg_ref})
            :                           %PAD_DEFAULTS;
 
    # Compute left and right spacings...
    my $gap   = $arg{cols} - length $text;
    my $left  = $arg{centered} ? int($gap/2) : 0;
    my $right = $gap - $left;
 
    # Prepend and append space...
    return $arg{filler} x $left . $text . $arg{filler} x $right;
}


print '[', padded( 'cell' ), "]\n";