org-babel for haskell not works of eval haskell block

Question

I am use org-mode blogging, I use org-babel to evaluate the code as following :

#+BEGIN_SRC haskell
import Data.Function (fix)

f :: Int -> Int
f = (+ 1)

main :: IO ()
main = do
      putStrLn $ show $ f 1
#+END_SRC

#+RESULTS:
: <interactive>:9:25: Not in scope: ‘f’

I found the org-babel for haskell use infer-haskell mode to start session and eval the code. I also say the session was created, and if I don't define the function but directly putStrLn "hello" , it works.

hope anyone can fix the bug :)

Genevieve

Answer 1

#+BEGIN_SRC haskell
import Data.Function (fix)

f :: Int -> Int
let f = (+ 1)

main :: IO ()
main = do
      putStrLn $ show $ f 1
#+END_SRC

#+RESULTS:
: 2

Org's babel mode is running the Haskell code with ghci. In ghci you are required to use let to declare functions.

Thereafter

I do wonder how tangle handles extracting this to a source file since let f would be invalid in a Haskell source file. For those not familiar with tangle: orgmode.org/manual/Extracting-source-code.html – Thereafter

I'm a couple years late but to clear it up for everyone who stumbles upon this: it simply doesnt, tangle doesn't work properly when combined with variables in haskell – Typeset

Answer 2

In this article, Yoshinari Nomura describes a way to evaluate Haskell blocks using runhaskell via a Ruby script. I do not understand japanese, so I cannot translate the details, but the method has allowed me to run haskell blocks without having to write specifically for the interpreter.

Homelike

This saved my day after trying around for 2 hours ... thanks. – Flunk