Overkill. Wouldn't something like: 
$system = "LMN" if $sender eq 'abc' or $domain eq 'xyz' or $message =~
+ /DEF/;

[download]
do? If your real question is "how to get the headers out of an email", use one of the gazillion e?mail related CPAN modules,

In reply to Re: Parse::RecDescent question by JavaFan
in thread Parse::RecDescent question by fionbarr

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