I need to sort a hash based on the values of two keys. The hash holds pairs of numbers, where the pair is covered with keys named 'start' and 'end'. When sorting these pairs, the problem is in dealing with cases in which the start or the end of one pair is identical with the start or end of a different pair. For the following set of pairs, I want a sort of the hash that produces exactly this ordering:
3:7, 10:30, 10:15, 15:25, 27:30, 35:40
The problem cases are the ones in which one of the pair parts is identical with one of the parts of a different pair (seen in tokens 2 through 5 above). To make what I'm after a little clearer, you can think of token 2 as 'surrounding' tokens 3 through 5, or, tokens 3 through 5 are 'inside' or a subpart of token 2.
What's a good way to do this kind of sorting of a hash in Perl?
Thanks for your help.