Options

1.1

Introduction

Options is a class giving you the ability to easily parse optionfiles in your perl programms.
With Options you can implement a hierarchical option structure which this class can parse into a single anon perl hash structure or you can extrace single options.
To implement a hierarchic structure you must seperate options attributes using a ".".
The main syntax of an optionline is:

attribute[.attribute[..]] = value

Blank lines or lines starting with a # (hash-sign) will be ignored during parsing.

Lets construct an example optionfile for configuring cars and their attributes.
We call our optionfile "cars.properties" and it looks like this:

  audi.tt.doors = 2
  audi.tt.ps = 250
  audi.a4.doors = 4
  audi.a4.ps = 130
  porsche.cayenne.doors = 4
  porsche.boxter.doors = 2

Now you got two options.

• Parse a single option value
• Parse whole optionsfile into a anon perl hash

Lets consider you want to parse a single value: audi.a4.ps

  my $psAudiA4 = $caropts->getProperty("audi.a4.ps");

$psAudiA4 will now hold the value "130".

Lets consider you want to parse the whole option file.

  my $caroptsStruct = $caropts->getCompleteConfig();

No $caroptsStruct will have the following layout:

  $caroptsStruct->{audi}->{tt}->{doors} = 2
  $caroptsStruct->{audi}->{tt}->{ps} = 250
  $caroptsStruct->{audi}->{a4}->{doors} = 4
  $caroptsStruct->{audi}->{a4}->{ps} = 130
  $caroptsStruct->{porsche}->{cayenne}->{doors} = 4
  $caroptsStruct->{porsche}->{boxter}->{doors} = 2

Author

Markus Mazurczak <coding@markus-mazurczak.de>

Bugtracking

If you find any bugs or want to have a particular feature included register at http://mantis.markus-mazurczak.de

Dependencies

• strict - Should be a core module
• warnings - Should be a core module
• File::Basename - Should be a core module
• File::Spec - Should be a core module
• Merror - Download it from http://markus-mazurczak.de/?p=40

Installation

Download and unpack Options into a directory your perl programm can access and also put Merror.pm into the same directory as Options.pm

Error handling

Options uses the Merror class to implement error handling with a stacktrace function. The Merror object will be accessible through the MERROR member of the Options object.
E.g.: $opts->{MERROR}->error();

Example

Lets create the following directory structure: $HOME/src/test

• lib/
  • Merror.pm
  • Options.pm
• properties/
  • cars.properties
• test.pl
  And test.pl looks the following:

  #!/usr/bin/perl
  BEGIN {
         use strict;
         use warnings;
         use File::Spec;
         use File::Basename;
         use Data::Dumper;
  
         push(@INC, File::Spec->rel2abs(dirname($0))."/lib");
  }
  
  use Merror;
  use Options;
  
  my $optfile = File::Spec->rel2abs(dirname($0))."/properties/cars.properties";
  
  my $options = Options->new($optfile);
  if($options->{MERROR}->error()) {
         print("Error code: " . $options->{MERROR}->ec . "\n");
         print("Error description: " . $options->{MERROR}->et . "\n");
         print("Stacktrace:\n");
         $options->{MERROR}->stacktrace;
         exit(0);
  }
  
  my $fullopts = $options->getCompleteConfig();
  
  print Dumper($fullopts);
  
  my $audiA4Doors = $options->getProperty("audi.a4.doors");
  
  print("Audi A4 doors: $audiA4Doors\n");
  

  The output will be the following:

  nexus@hoare: ~/src/perl/test$ ./test.pl
  $VAR1 = {
           'porsche' => {
                          'boxter' => {
                                        'doors' => '2'
                                      },
                          'cayenne' => {
                                         'doors' => '4'
                                       }
                        },
           'audi' => {
                       'a4' => {
                                 'doors' => '4',
                                 'ps' => '130'
                               },
                       'tt' => {
                                 'doors' => '2',
                                 'ps' => '250'
                               }
                     }
         };
  Audi A4 doors: 4
  

Now lets assume that we got no read permissions on cars.properties
than the output will look like the following:

Error code: -1
Error description: Could not read option file: /home/nexus/src/perl/test/properties/cars.properties
Stacktrace:
Level: 0 -- File: /home/nexus/src/perl/test/lib/Merror.pm -- Pkg: Merror -- Sub: Merror::fillstack -- Line: 131
Level: 1 -- File: /home/nexus/src/perl/test/lib/Options.pm -- Pkg: Options -- Sub: Merror::error -- Line: 208
Level: 2 -- File: /home/nexus/src/perl/test/lib/Options.pm -- Pkg: Options -- Sub: Options::checkOptfile -- Line: 100
Level: 3 -- File: ./test.pl -- Pkg: main -- Sub: Options::new -- Line: 17