Both are saying "The caller does not provide a defined value", but there is no hint why you need two different ways to say that

My guess is that it's the difference "the caller does not have/want a value for this" and "the caller forgot to specify the value"

Take one example: A program called SchrödingersCat needs a command line flag to specify if the cat is alive or dead. But when called with a value of "undef", the caller provides a valid value of "we don't know if the cat is alive or dead". See Tom Scott's video on Null Island: The Busiest Place That Doesn't Exist

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In reply to Re^2: Existing module for PerlX::Maybe except for hash existence? by cavac
in thread Existing module for PerlX::Maybe except for hash existence? by Corion

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