say "[$-[0], $+[0])" while "aaaaa" =~ /a*?/g;

##</code><code>##

[0, 0)
[0, 1)
[1, 1)
[1, 2)
[2, 2)
[2, 3)
[3, 3)
[3, 4)
[4, 4)
[4, 5)
[5, 5)