[Haskell] new to haskell

wenduan xuwenduan2010 at gmail.com
Sat May 21 17:52:33 EDT 2005


hi all,
I'm new to haskell and just reading the "yet another haskell tutorial".I 
got stuck on the exercise of chapter 3,the problem goes like "repeatedly 
prompt the user to input some number until a zero is detected,then 
output the sum,product of those numbers and the factorial of each 
number." What I have done is I have an IO action up and running in a 
module I defined as following:

module Main where
main = do
   calculate

calculate   = do
     putStrLn "Give me a number (or 0 to stop):"
     number <- getLine
     let n = read number
     if n == 0
           then do
              return []
           else do
               rest <- calculate
               return (number : rest)
Now the question is I couldn't get any clue from the first three 
chapters to do the remaining calculation,what I wanted to do is to get a 
list out of the IO action I just defined, and do the sum,product and 
factorial out of the list,I tried something like"list <- calculate, sum 
list,etc,but it wasn't helpful,so would anyone just give me any hint to 
solve this,sorry for those who feel its quite basic.

-- 
-------------------------------------------------------------------------------------------------------
If you didn't succeed at the first attempt, you are just about average. 



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