ch08.022_best

Perl Best Practices the source code

##############################################################################
##   Code fragment (Recommended) from Chapter 8 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;

my $sales_data = \*DATA;
my @sales;

sub translate_ID {
    my ($id) = @_;
    return $id;
}

my $file_name = 'Whatever';

sub get_layout {
    return 'Spaced';
}


# Specify order and lengths of fields...
Readonly my %RECORD_LAYOUT  => (
              #  Ident   Sales   Price
    Unspaced => '    A6     A10      A8',   # Legacy layout
      Spaced => ' @0 A6  @8 A10  @19 A8',   # Standard layout
     ID_last => '@21 A6  @0 A10  @12 A8',   # New, more convenient layout

);
 
# Select record layout...
my $layout_name = get_layout($file_name);

 
# Grab each line/record...

while (my $record = <$sales_data>) {
 
    # Extract all fields...
    my ($ident, $sales, $price) 
        = unpack $RECORD_LAYOUT{$layout_name}, $record;

 
    # Append each record, translating ID codes and
    # normalizing sales (which are stored in 1000s)...
    push @sales, {
        ident => translate_ID($ident),
        sales => $sales * 1000,
        price => $price,
    };

}



use Data::Dumper 'Dumper';
warn Dumper [ @sales ];


__DATA__
X123-S  0000013247  00000199
SFG-AT  0000000102  00009099
Y811-Q  0000100300  00000033