On Wed, Apr 24, 2013 at 10:47 AM, Duncan Coutts <duncan.coutts@googlemail.com> wrote:

I address it briefly in my thesis [1], Section 4.8.2. I think it's a
fundamental limitation of stream fusion.

See also concat, where the naive fusion-based implementation has quadratic performance:

concat :: [Text] -> Text

concat txts = unstream (Stream.concat (List.map stream txts))

I've never figured out how to implement this with sensible characteristics within the fusion framework.