I've got a script that is part of a larger collection of "tools" I use on a cron'ly basis for mirroring and administration of some distributed servers in a cluster, and it basically wraps a system binary which takes roughly 40 possible arguments.

What I've got thus far, is modified via an email sent to a specific (secured) account on an internal control box. In this email body is a template, pseudo-XML, which contains the options I want to pass to the system binary in 'key = value' pairs, and looks like this:

   <tmpl>
      foo   = 1
      bar   = SomeThing
      blort = 2003-06-29
   </tmpl>
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I detach this template from the body of the email with Mail::Internet as follows:

   my $message     = new Mail::Internet ([<>]);
   my @body        = @{$message->body()};
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From here, I parse it out with Config::General, and end up with things like this:

   my %config      = $conf->getall;
   my $template    = $conf->obj('tmpl');
   my $foo         = $config{'tmpl'}->{'foo'};
   my $bar         = $config{'tmpl'}->{'bar'};
   my $blort       = $config{'tmpl'}->{'blort'};
   # ... up to 40 possible values
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When I have these all in scalars, I go through them one-by-one, and validate each, to make sure I didn't pass any typos or other invalid values. for example, the key 'foo' in the template can only take a digit, so I can restrict that, and check it. The next key, 'bar' may only take a common word, starting with a capital letter. I can also check that. You can see how lengthy this gets after 40 possible values need to be stuffed into scalars and checked for proper syntax and validity.

Is there a better way to parse, accept, and validate each of these values from the template, without duplicating 40 separate checks for each value that can be passed?