Compiling a haskell script with external dependencies without cabal

Question

I'm relatively new to Haskell and I realize I might be swimming against the stream here, but nonetheless, I'll ask:

Say I have a short Haskell script:

import Data.List.Split (splitOn)

main :: IO ()
main = do
  let orders = splitOn "x" "axbxc"
  putStrLn $ head orders

If I used only standard functions I could compile this with ghc <script.hs>. Because I depend on the split package to provide the splitOn function, the compilation fails.

Now, I have no difficulties setting up a cabal project with a project.cabal and a Setup.hs file in order to get this to actually compile. However, this feels like a lot of extra boilerplate for a standalone script.

So, is there a way to compile a single .hs file against some external package? Something similar to what in Python would be done by pip install something, "installing the package into the interpreter", i.e. is there a way to install extra packages "into ghc", so that I for instance only need to provide some extra linking flag to ghc?

Answer 1

The Cabal equivalent of the Stack script in bradrn's answer would be:

#!/usr/bin/env cabal
{- cabal:
build-depends: base
            , split
-}

import Data.List.Split (splitOn)

main :: IO ()
main = do
  let orders = splitOn "x" "axbxc"
  putStrLn $ head orders

The script can be run with cabal run, or directly by giving it execute permission. If need be, version bounds can be added as usual to the build-depends on the top of the script.

(Note this isn't literally a solution without Cabal, as doing this with GHC alone, even if it is possible, wouldn't be worth the trouble. In any case, it certainly avoid the boilerplate of needing multiple files.)