The inherent weakness in your query is that you are asking for a Perl equivalent to a basic 'switch' idiom, when Perl doesn't provide a 'switch' construct.

You are asking about Duff's Device ..... which, as I remember, was invented to save a couple dozen machine instructions. My understanding is that Duff's Device is mostly viewed as poor programming, since saving a few dozen machine cycles at 3 GHz is less important than leading to quick and clear reader understanding of the code. On the other hand, I can imagine programmers dealing with highly-efficient code, such as embedded programmers, might accept Duff as an easily recognized idiom.

So the next question is, without a switch statement, how would we implement Duff?

We've had one suggestion, using substr(), very closely related to the details of this question.

More generally, you might consider re-framing the conditionals:

for my $val ( $var ) {
    print "a" if ( $val >= 10 );
    print "b" if ( $val >= 9 );
    print "c" if ( $val >= 8 );
    print "d" if ( $val >= 7 );
    print "e" if ( $val >= 6 );
    print "f" if ( $val >= 5 );
    print "g" if ( $val >= 4 );
    print "h" if ( $val >= 3 );
    print "i" if ( $val >= 2 );
    print "j" if ( $val >= 1 );
}
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So, yes, it can be achieved, but you need to think somewhat differently.