atzeus/sequence

sequence's Issues

Should Sequences be Applicatives or Monads?

It would be very easy to add Applicative or even Monad as a superclass for Sequence. The main downside is that this forces a choice of instance. I believe the Monad [] instance is probably the only reasonable choice, but there's also the Applicative ZipList instance. Still, something to think about. If we did require it, then we'd be able to snag an Alternative instance, which would be pretty.

FastQueue is broken

I don't have a specific test case, but I get invariant failures from it. I was able to fix that by adding a case to rotate:

rotate :: [a] -> [a] -> [a] -> [a]
rotate [] [] r = r
rotate []  [y] r = y : r
rotate (x : f) (y : r) a = x : rotate f r (y : a)
rotate _f _a _r  = error "Invariant |a| = |f| - (|r| - 1) broken"

I can't guarantee that's the right fix, but it seems to work.

Add a test suite