Fibs in Prana

0_fib-iter.hs

fib :: Int -> Int
fib n = go 0 1 0
  where
    go !acc0 !acc1 !i
      | i == n = acc0
      | otherwise = go acc1 (acc0 + acc1) (i + 1)

it :: Int
it = fib 50

{-

Output:

main:Fib.it = 
(ghc-prim:GHC.Types.I# (IntLit 12586269025))
581.80 us

-}

1_fib-codata.hs

fibs = 1 : 1 : zipWith (+) fibs (tail fibs)

taker :: Int -> [Int] -> [Int]
taker count xs = go 0 xs
  where go cur xs | cur == count = []
        go cur [] = []
        go cur (x:xs) = x : go (cur+1) xs

it :: [Int]
it = taker 10 fibs

{- 

Output:

main:Fib.it = 

(ghc-prim:GHC.Types.: (ghc-prim:GHC.Types.I# (IntLit 1)) (ghc-prim:GHC.Types.: (ghc-prim:GHC.Types.I# (IntLit 1)) (ghc-prim:GHC.Types.: (ghc-prim:GHC.Types.I# (IntLit 2)) (ghc-prim:GHC.Types.: (ghc-prim:GHC.Types.I# (IntLit 3)) (ghc-prim:GHC.Types.: (ghc-prim:GHC.Types.I# (IntLit 5)) (ghc-prim:GHC.Types.: (ghc-prim:GHC.Types.I# (IntLit 8)) (ghc-prim:GHC.Types.: (ghc-prim:GHC.Types.I# (IntLit 13)) (ghc-prim:GHC.Types.: (ghc-prim:GHC.Types.I# (IntLit 21)) (ghc-prim:GHC.Types.: (ghc-prim:GHC.Types.I# (IntLit 34)) (ghc-prim:GHC.Types.: (ghc-prim:GHC.Types.I# (IntLit 55)) (ghc-prim:GHC.Types.[])))))))))))

28.68 us

  Case  Allocated  GCs  Max
  Eval    886,680    0    0

-}