my $diffs = diff( .... );
for my $diff ( split ' ', $diffs ) {
    my( $start, $len ) = split ':', $diff;
    ## use start / len
}

##</code><code>##

my $ref = diff( ... );

for my $pair ( @{ $ref } ) {
    my( $start, $len ) = @{ $pair };
    ## use start / len
}