repa also has some unfortunate lacunae, either in the API or in the documentation.
For instance, one thing I tried to do but couldn't - apply `scanl` to an array with a piece of intermediate state that is threaded through the computation, save the piece of state at the end, and then apply `scanr` to the same array, using the piece of state from the application of `scanl`.
For instance, one thing I tried to do but couldn't - apply `scanl` to an array with a piece of intermediate state that is threaded through the computation, save the piece of state at the end, and then apply `scanr` to the same array, using the piece of state from the application of `scanl`.