dune scripts

[oberblastmeister]

Haskell's cabal supports this

#!/usr/bin/env cabal
{- cabal:
build-depends: base ^>= 4.11
            , shelly ^>= 1.8.1
-}

main :: IO ()
main = do
    ...

The script can be made executable and running it will automatically download and build dependencies, compile the script, and then execute it. Subsequent runs where the file hasn't been changed will use the cached compilation. More information here https://cabal.readthedocs.io/en/stable/getting-started.html#running-a-single-file-haskell-script

With the advent of dune package management, we could do the same thing. For example:

#!/usr/bin/env dune
(* dune:
(depends
 base
 feather)
*)

open Feather

let () =
  process "ps" [] |. map_lines String.uppercase |. grep "BASH" |> run

This could make OCaml a nice replacement for shell scripts.

[nojb]

@oberblastmeister Independently of any package management, this sounds like a nice feature for one-file projects!

Question: where does cabal store its build artifacts when running a one-file script in this way? Next to the script?