$encode = 'p';
$sub_ref = test($encode);

sub test
{ my $e = shift;
  my $eval1 = 'print "first bit of reusable code\n";';
  my $eval2 = 'print "second bit of reusable code\n";';

  $e eq 'p'? return sub
  { eval $eval1;
    print "you typed 'p' as your option\n";
    eval $eval2;
  }:
  $e eq 'b'? return sub
  { eval $eval1;
    print "you typed 'b' as your option\n";
    eval $eval2;
  }:
  return sub
  { eval $eval1;
    print "you typed 'u' as your option\n";
    eval $eval2;
  };
}

$encoded_output = &$sub_ref;