parse-package-imports.sh

package-import-nix-shell.sh

#! /usr/bin/env bash

set -euo pipefail
shopt -s inherit_errexit

packagesRaw=$(./parse-package-imports.sh $1)
shift
readarray -t foundPackages <<< "$packagesRaw"

nix="haskellPackages.ghcWithPackages (pkgs: with pkgs; [ ${foundPackages[@]} ])"
nix-shell -p "$nix" "$@"

parse-package-imports.sh

#! /usr/bin/env bash

set -euo pipefail
shopt -s inherit_errexit

file="$1"

regex='^import[[:space:]]*"([A-Za-Z0-9-]+)"'

while IFS= read -r line
do
    if [[ $line =~ $regex ]]
    then
        echo "${BASH_REMATCH[1]}"
    fi
done < "$file"

test1.hs

{-# LANGUAGE PackageImports #-}
module Whatever where

import "puhoy" OI
import "there" THERE

import HMM

import "lol" LOL

x :: Int
x = 2

s :: String
s = "import \"hi\" HI"

test2.hs

{-# LANGUAGE PackageImports #-}
module Main where

import "timeit" System.TimeIt

main :: IO ()
main = timeIt $ putStrLn "puhoy there!"

Seems to work:

$ ./package-import-nix-shell.sh test2.hs --run "runghc test2.hs"
puhoy there!
CPU time:   0.00s

Sanity check of the parser:

$ ./parse-package-imports.sh test1.hs
puhoy
there
lol

$ ./parse-package-imports.sh test2.hs
timeit