我一直試圖做的Haskell中2nd Project Euler problem,但我已經得到:Occurs check: cannot construct the infinite type: a = [a]
出現,請檢查:無法構造無限類型:A = [A]
fibonacci 0 _ = 0
fibonacci 1 _ = 1
fibonacci x xs = (xs!!(x-2)) + (xs!!(x-1))
fibonaccisLessThan = takeWhile(<40) $ foldr fibonacci [] [0..]
sumOfEvenFibonaccis = sum $ filter even $ fibonaccisLessThan
main = putStrLn $ show $ sumOfEvenFibonaccis
有人能告訴我爲什麼嗎?
如果你能給錯誤的路線,那將是很好的。作爲一個側面說明,當你有多個'$'時,你通常希望使用合成來優雅。 – alternative 2011-04-03 11:41:14