That's not a good example, because Fortran 90 compilers will (mostly) accept code written for 77. There's nothing holding you back from upgrading and still using the old stuff. Which sounds like what Perl 6 will be like, too.

And because I like to point this out: In Fortran, spaces between columns 7 and 72 do not matter unless they are between quotes.

For example:

if( foo .eq. bar ) then

is equivalent to

i    f(f    oo.e     q.b    ar)t     hen

And people have the nerve to call Perl unreadable!