The reference to @_ in find_gaps should actually be keys %{ $_[0] }. From there, I ran it with the following dates (first line of dates from my test suite): 
2000-4 2000-2 2000-1 2000-12 2001-1 2002-12 1999-12

[download]
The output: 
$VAR1 = '2000-3';

[download]
It found the first gap but not the rest.

Cheers,
Ovid

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In reply to (Ovid - nice try)Re: Re (tilly) 1: Finding gaps in date ranges by Ovid
in thread Finding gaps in date ranges by Ovid

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