I've received a request for DBM::Deep to allow for pure-perl versions of various modules, such as Digest::MD5 and Digest::MD5::Perl. The solution when loading is to eval the use and fail appropriately. However, I'm not quite sure how to do the dependencies for Module::Build (or ExtUtils::MakeMaker). Essentially, I want to go through the following steps:
  1. Do you have Digest::MD5 installed?
  2. If not, do you have Digest::MD5::Perl installed?
  3. If not, ask which one you want to have installed.
Is this a feature of MB or EUMM? If not, what would the simplest way of putting this into my Build.PL (or Makefile.PL - I'm willing to switch back) be?
My criteria for good software:
  1. Does it work?
  2. Can someone else come in, make a change, and be reasonably certain no bugs were introduced?

In reply to Either-or dependencies by dragonchild

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