Params::Check looks like it is the right module for use here, and I managed to get it working, somewhat (with a slight syntax poke/help from jeffa). Now the problem is that I need to generate a custom error message when the params are incorrect (instead of the generic die "Could not parse arguments\n"; message).

For example, if I accept a date range in 'blort' above ($conf{'template'}->{'blort'}) of the format YYYY-MM-DD, and the value supplied by the template's value in that key is DD-MM-YYYY, I would like to die with an error specific to that key, and then return a list of the proper syntax, such as:

  "Date format incorrect, please supply the date
   in the format YYYY-MM-DD for proper parsing."
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How would I go about doing that? I see that in Params::Check, I can run another sub inside the accept() object to pass the args, and validate that way, but now I'm back to doing ~40 different calls to that check, which is back to where I started.