The Problem:
I have some Perl Modules, each of which has its own config file containing a rather complex data structure. The Modules are structured in a hierarchy and depend quite heavily on inheritance. Now I would like to use inheritance with the config values to e.g. specify a default value in one package and override it in another.

It look sort of like this:

package Parent;
require ('./parent.cfg');

package Parent::Child;
@ISA=('Parent');
require ('./child.cfg');

package Parent::Child2;
@ISA=('Parent');
require ('./child2.cfg');

package Parent::Child::Grandchild;
@ISA=('Child');
require ('./grandchild.cfg');
[download]

A config file looks like:

$config={
    string=>"bla",
    array=>['val1','val2'],
    hash=>{
        foo=>'bar',
    },
# etc, put any valid perl data structure here    
};
[download]

My not-so-ideal solution: I wrote a routine (called "config") that returns config value associated with the given key. If the key is not found in %config of the calling package, the next upper package is searched, following @ISA.

This works quite OK, but it is sort of very inconvient to change values in arrays or hashes. If I want to override a part of list of some sort, I have to put the new complete list in the Child-Config.

Eg:

in parent.cfg
#...
    list=>['val1','val2','val3'],

in child.cfg
#...
    list=>['val1','val2','val3','FOO','BAR'],
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This results in a lot of very similar config entries.

What I want:
I would like to do something like that:

parent.cfg:
%config=(
    # complex data structur
)

child.cfg:
config_add('newval',$datastruct);
config_remove('DontNeedThisHere');
config_push('array',$newval,$anotherval);
# and some other data manipulation routines
[download]

the changes in child.cfg should only be visible in Parent::Child ,e.g
if you do
print scalar (@{Parent->config('array')})
it should print "26", but
print scalar (@{Parent::Child->config('array')})
should print "28".

Finally, my questions:

• Before I implement it own my one: Is there a module on CPAN that implements some of this functionality? I couldn't find one.
• If not, have you got some Namespace suggestions? I was think of something like Data::Inheritable or Data::OO
• Do you know of another place to ask this questions?

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