Is there another way to use given...when... in a "functional" way which avoids introducing a do statement and a dummy lexical?
No, in the same way you cannot do 
my $r = if ($foo) then {"bar"} else {"baz"};

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or 
my $r = for (1, 2, 3) {$_ + 4};

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But you can in ALGOL 68! ;-)

In reply to Re: functional "given...when..."? by JavaFan
in thread functional "given...when..."? by perl5ever

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