Hello Café, I've used Haskell and GHC to solve particular real life application. 4 tools were developed and their function is almost the same - they modify textual input according to patterns found in the text. Thus, it is something like a compiler, the result is also a text and it is not parsed to tokens as patterns appear on a different level. The tools differ in tasks and number of modifications performed, otherwise, in principal, they are very much similar. I used lists (Prelude, Data.List) to develop the tools. After successfully completing the development, I've started to optimize the code to make the tools faster. After modification of some algorithms (which dropped the processing time notably), I started to change data structures. I swapped lists with lazy bytestrings. Nevertheless, what an unpleasant surprise, the processing speed dropped down, significantly / more then 30% time needed). So my questions follow: - What kind of application is lazy bytestring suitable for? - Would it be worth using strict bytestring even if input files may be large? (They would fit in memory, but may consume whole) - If bytestring is not suitable for text manipulation, is there something faster than lists? - It would be nice to have native sort for lazy bytestring - would it be slower than pack $ Data.List.sort $ unpack ? - If bytestring is suitable for text manipulation could we have some hGetTextualContents which translates Windows EOL (CR+LF) to LF? I'm sorry if the answers are obvious. Could anyone point me to some article/pages I could read about? Thanks and regards, John -- http://www.fastmail.fm - A fast, anti-spam email service.