Tested with : GHC 6.6

Stream fusion for sequences. Described in:

• Stream Fusion: From Lists to Streams to Nothing at All, by Duncan Coutts, Roman Leshchinskiy and Don Stwwart, ICFP 2007. http://www.cse.unsw.edu.au/~dons/papers/CLS07.html
• Rewriting Haskell Strings, by Duncan Coutts, Don Stewart and Roman Leshchinskiy, Practical Aspects of Declarative Languages 8th International Symposium, PADL 2007, 2007. http://www.cse.unsw.edu.au/~dons/papers/CSL06.html

See the source for the complete story:

• http://www.cse.unsw.edu.au/~dons/code/streams/list/Data/Stream.hs