Based on your statement "on each encountered date run spcial sub to process each date input," it sounds to me like when you build your dataset, you should consider putting it into a hash. Have your keys be the actual data you want to juggle. You can then give the value for each key a "datatype" of DATE, NAME, AGE, etc.

-pseudoexplanation of hash NOT PROPER CODE-

my %Data;
$Data{'Bob'} = "NAME";
$Data{'1234 Perl Way'} = "ADDRESS";
$Data{'5'} = "AGE";
$Data{'1/2/02'} = "DATE";
$Data{'3/4/02'} = "DATE";
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and so on

I will admit, it is pretty crude, and counts on the fact that you know what data is going into the set, but hey, it would work for what you want, and it would be relative easy to iterate over.

Oh, and it is likely to be viewed as a backwards way to use a hash. hee hee