Fair criticism, though I would point out the total lack of context on the question at large. How about a compromise, which still lets the user specify their subroutine with a string, as per spec:

#!/usr/bin/perl
use strict;
use warnings;

my $sub_name = 'do_this';
my %dispatch_table = (do_this => \&do_this,
                      do_that => \&do_that,
                      );


print $dispatch_table{$sub_name}("Fred");

sub do_this {
   my $var = shift;
   return "My name is $var";
}

sub do_that {
   my $var = shift;
   return "My name is not $var";
}
__END__
My name is Fred
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