When writing a haskell script, get syntax error near unexpected token

Question

When I write a simple script and pass it to runhaskell, it works fine, but not when I add a shebang and try executing it directly. The script is this:

#!/usr/local/bin/runhaskell

import Data.List (intercalate)

main :: IO ()
main = putStrLn $ intercalate " " $ map show [1..10]

If I try $ runhaskell count.hs bash prints 1 2 3 4 5 6 7 8 9 10 as expected, but if I try ./count.hs I get the following error:

./count.hs: line 3: syntax error near unexpected token `('
./count.hs: line 3: `import Data.List (intercalate)'

Is this error originating in bash or runhaskell? And how do I fix it?

Answer 1

Try using:

#!/usr/bin/env runhaskell
...

Note: this is a feature/issue with OSX where shebang interpreters are required to be binaries. See Shebang pointing to script (also having shebang) is effectively ignored for more details.