not really, does this $subject =~ "some other subject" mean you wanna match on regexes?

You could use a nested hashes to hold all criterias and easily loop over them, but I would stick with real code to stay flexible.

Perl can be very compact, see all the examples in Given When Syntax, especially Re^2: Given When Syntax.

Instead of nesting switch $body => HASHREF statements you could just write three subs if_body ARRREF and so on and define your own little domain specific language. (array cause order seems to matter)

if_sender [
  "sender A" => 
      if_subject [
         "some text" =>
              if_body [
                 "some other text" => sub {return "type 1";},
                  ...
                      ],
              ...
                 ],
          ...
          ];
[download]

Of course you are free to just use nested arrays and to assign each level to one fixed criteria when looping.¹

A simple string would mean test string equality, a qr/regex/ test for match. HTH! :)

update

¹) then you might wanna use YAML as input format to simplify writing