I’ve experimented with different types of markup language to store small amounts of data, usually for config files, but never found something that quite did what I want. Of course, if I could define what I wanted, I’d be in a better position to find it.

The .ini style of files is all right, and there are lots of perl modules to deal with them (and finding the right one is a pain), but this style of files doesn’t allow for any data structures other than key=value.

I looked at an Apache style of config file, and this worked ok, but again, using the data structures is a bit of a pain (ie cracking out a new container each time I needed a hash, and very poor handling of arrays). The modules I tried also had problems with inheritance, for example

firstlevel container name=a
key = value
secondlevel container name=”foo”
blah = quux

Here, foo is on the same level as key. So if I ask the foo container the value of “key”, I should get “value”. Some modules did this, but when I wanted to iterate through all the secondlevel containers, I couldn’t.

So, I happened to come across YAML, and Config::YAML

The YAML for the Config::YAML’s CPAN entry is

 # http://module-build.sourceforge.net/META-spec.html

 #XXXXXXX This is a prototype!!!  It will change in the future!!! XXXXX#

 name:         Config-YAML

 version:      1.28

 version_from: lib/Config/YAML.pm

 installdirs:  site

 requires:

    Test::More:                    0

    YAML:                          0.35

 distribution_type: module

 generated_by: ExtUtils::MakeMaker version 6.17

It uses spaces to denote hierarchy (pythonesque, eh?), and the data structure returned is

$VAR1 = bless( {
‘installdirs’ => ‘site’,
‘distribution_type’ => ‘module’,
‘generated_by’ => ‘ExtUtils::MakeMaker version 6.17’,
‘version’ => ‘1.28’,
‘name’ => ‘Config-YAML’,
‘_infile’ => ‘app.yaml’,
‘version_from’ => ‘lib/Config/YAML.pm’,
‘requires’ => {
‘Test::More’ => 0,
‘YAML’ => ‘0.35’
},
‘_outfile’ => ‘app.yaml’
}, ‘Config::YAML’ );

No, it doesn’t do inheritance, but I think I could wrap something around that when I need it. However the simplicity and flexibility in the config file is wonderful.