ch02.044_prob

Perl Best Practices the source code

##############################################################################
## Code fragment (NOT RECOMMENDED) from Chapter 2 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 $EMPTY_STR => q{};

my $raw;

sub addarray_internal {
    my ($var_name, $needs_quotemeta) = @_;
    # Cache the original...
    $raw .= $var_name;
    # Build meta-quoting code, if required...
    my $quotemeta = $needs_quotemeta ?  q{map {quotemeta $_} } : $EMPTY_STR;
    # Expand elements of variable, conjoin with ORs...
    my $perl5pat = qq{(??{join q{|}, $quotemeta \@{$var_name}})};
    # Insert debugging code if requested...
    my $type = $quotemeta ? 'literal' : 'pattern';
    debug_now("Adding $var_name (as $type)");
    add_debug_mesg("Trying $var_name (as $type)");
    return $perl5pat;
}