New in version 2.0.
Change rational to prolation string:
abjad> from abjad.tools import durationtools
abjad> generator = durationtools.yield_all_positive_rationals_in_cantor_diagonalized_order_uniquely()
abjad> for n in range(16): # doctest: +SKIP
... rational = generator.next()
... prolation_string = durationtools.rational_to_prolation_string(rational)
... print '%s\\t%s' % (rational, prolation_string)
...
1 1:1
2 1:2
1/2 2:1
1/3 3:1
3 1:3
4 1:4
3/2 2:3
2/3 3:2
1/4 4:1
1/5 5:1
5 1:5
6 1:6
5/2 2:5
4/3 3:4
3/4 4:3
2/5 5:2
Return string.