I don't know how to get rid of given, but you could make it look a little less redundant:

while (1) {
    given (<>) {
        when (…) {…}
        default { last }
    }
}
[download]

I think it would look prettier as

do {
    given (<>) {
        when (…) {…}
        default { last }
    }
} while 1;
[download]

but that gets you chastised about using last outside a loop block.

As others have observed, say '' is the same as print "\n". Have you thought about whether setting $\ will fulfil your needs?