This smells like homework to me, which isn't a bad thing, it will however change the way I answer you. Please look at http://hackage.haskell.org/packages/archive/base/latest/doc/ html/Data-List.html#v:permutations and show us your attempts to use this function. Timothy ---------- Původní zpráva ---------- Od: Rune Harder Bak <rune@bak.dk> Datum: 17. 11. 2012 Předmět: [Haskell-cafe] List all multiply/add combinations "Given a list of numbers of fixed length I need to list all possible values (and the associated computation) you get by inserting +,-,*,/ between the numbers, and also set parentheses where you please. It shouldn't list computations with unnecessary parentheses. Example list of length 3 [a,b,c] and only with + and *: a*b+c, a*(b+c),a*b*c,a+b*c,(a+b)*c,a+b+c What would be a good way to do this, and a good representation in Haskell? Best, Rune _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe (http://www.haskell.org/mailman/listinfo/haskell-cafe)"