Add 'subsequences' and 'permutations' to Data.List (ticket
dbenbenn at gmail.com
Thu Dec 20 12:25:20 EST 2007
It just occurred to me that permutations doesn't quite agree with the
>>> permutations "aaa"
But that's not really a problem, since you can always just compose
permutations with (Set.toList . Set.fromList).
On Dec 20, 2007 7:05 AM, Twan van Laarhoven <twanvl at gmail.com> wrote:
> Chris Kuklewicz wrote:
> > Unfortunately, permutations5 has an error:
I suggest including some QuickCheck properties with this proposal,
especially a property that would have caught that error. I'm thinking
of four properties:
1) If x = permutations y, then check length x is right.
2) Check each element of x is a permutation of y
3) Check each permutation of y is an element of x
4) Check for laziness
By the way, to improve mailing list laziness: the proposal is at
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