perl configuration file which contains variables? - perl

Question

I want to create a perl configuration file. I want a file format which has variables. So something like this:
DefaultDirectory = /var/myProgram/
OutputDirectory = $DefaultDirectory/output
InputDirectory = $DefaultDirectory/input
This seems simple, but I'm not sure what is available with perl. The perl ini options I see don't appear to support it. I looked into YAML, but it seems almost overkill.
Can anyone suggest a good file format and CPAN module that supports it which can support simple variables? I'm stuck with perl 5.5 so hopefully an older module.

Answer 1

Try Config::General.
test.cfg
# Simple variables
DefaultDirectory = /var/myProgram
OutputDirectory = $DefaultDirectory/output
InputDirectory = $DefaultDirectory/input
# Blocks of related variables
<host_dev>
host = devsite.example.com
user = devuser
password = ComeOnIn
</host_dev>
<host_prod>
host = prodsite.example.com
user = produser
password = LockedDown
</host_prod>
test.pl
#!/usr/bin/perl
use strict;
use warnings;
use Config::General;
my $conf = Config::General->new(
-ConfigFile => 'test.cfg',
-InterPolateVars => 1
);
my %config = $conf->getall;
print <<HERE;
Default directory: $config{'DefaultDirectory'}
Output directory: $config{'OutputDirectory'}
Input directory: $config{'InputDirectory'}
Development host: $config{'host_dev'}{'host'}
Development password: $config{'host_dev'}{'password'}
Production host: $config{'host_prod'}{'host'}
Production password: $config{'host_prod'}{'password'}
HERE
Output:
Default directory: /var/myProgram
Output directory: /var/myProgram/output
Input directory: /var/myProgram/input
Development host: devsite.example.com
Development password: ComeOnIn
Production host: prodsite.example.com
Production password: LockedDown

Answer 2

Have you considered just writing your own perl module that contains config?
Something like (MyConfig.pm):
package MyConfig;
our $DefaultDirectory = '/path/to/somewhere';
our $setting_for_something = 5;
1;
You can then import that with use MyConfig;. You may need to set use lib or FindBin to find the module first though (depends on where you invoke the script - use will search cwd).
But really - perl 5.5? That's .... well worth updating, given that's the version from 2004. I do hope you don't run too much stuff on 10 year old software - the world has changed A LOT in the intervening time. (And so has Perl)