[Haskell-cafe] Re: [Haskell] Recursive definition of fibonacci with Data.Vector

edgar:

Hello,

why I can't define a recursive vector using Data.Vector, like in the example:

import qualified Data.Vector as V

let fib = 0 `V.cons` (1 `V.cons` V.zipWith (+) fib (V.tail v))

There's a typo: fib = 0 `V.cons` (1 `V.cons` V.zipWith (+) fib (V.tail fib)) Which let's it typecheck. But I don't think this is a sensible use of vectors. In fact, infinite vectors make no sense, as far as I can tell -- these are fundamentally bounded structures. GHC even optimizes it to: fib = fib (literally!). $ time ./A A: <<loop>> -- Don