On Tue, Sep 25, 2007 at 10:53:55AM +0100, Andrew Coppin wrote: > Tristan Allwood wrote: >> >> Just to follow those sentiments, the version I knocked out quickly >> looked like: >> (It's not quite the same as the original function, I think I'm lacking a >> map (map (take 8)) on the first line). >> >> showSystems :: Show a => [[a]] -> String >> showSystems = unlines . zipWith showSystem [1..] >> where >> showSystem n as = "Eq" ++ (show n) ++ ": " ++ sum ++ " = " ++ val >> where >> sum = concat . intersperse " + " . zipWith showNum [1..] $ (init >> as) >> val = show . last $ as >> showNum n a = show a ++ " x" ++ show n >> >> > > I'm puzzled - do we have 2 seperate where clauses?
Yes there are 2 and no they arn't seperate. The second where clause is nested and is a set of definitioins local to showSystem, and as such can use the bound values of n and as. (But it can also "see" any values bound by showSystems and its where clause (which in this case is just the definition of showSystem). Clear as mud? T -- Tristan Allwood PhD Student Department of Computing Imperial College London _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
