I was just meditating on array fusion using streams, and list fusion using
streams, and it struck me: the definition of the list functions over arrays
is the same as that of the list functions over lists. From the ByteString
paper, we get:
map f = transformerBi (mapS f)
foldr f z = consumerDn (foldrS f z)
foldl f z = consumerUp (foldlS f z)
replicate n = producerBi (replicateS n)
etc.
So why not say
class Sequence t alpha where
consumerUp, consumerDn, consumerBi
:: (Stream alpha -> beta) -> t alpha -> beta
producerUp, producerDn, producerBi :: Stream alpha -> t alpha
transformerUp, transformerDn, transformerBi
:: Sequence t beta => (Stream alpha -> Stream beta) -> t alpha -> t beta
map :: Sequence t alpha => (alpha -> beta) -> t alpha -> t beta
map f = transformerBi (mapS f)
etc.?
Jonathan Cast
http://sourceforge.net/projects/fid-core
http://sourceforge.net/projects/fid-emacs
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