Initial commit

.gitignore

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+.stack-work/
+elm2nix.cabal
+*~

ChangeLog.md

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+# Changelog for elm2nix
+
+## 0.0.1.0 (2017-12-14)
+
+- Initial release (Domen Kožar)

LICENSE

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+Copyright Domen Kožar (c) 2017
+
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+    * Redistributions of source code must retain the above copyright
+      notice, this list of conditions and the following disclaimer.
+
+    * Redistributions in binary form must reproduce the above
+      copyright notice, this list of conditions and the following
+      disclaimer in the documentation and/or other materials provided
+      with the distribution.
+
+    * Neither the name of Domen Kožar nor the names of other
+      contributors may be used to endorse or promote products derived
+      from this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

README.md

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+# elm2nix (alpha/unstable)
+
+Convert Elm project into Nix expressions.
+
+## Installation
+
+  $ stack install --nix
+
+## Usage
+
+  $ cd my-project
+  $ ~/.local/bin/elm2nix init > default.nix
+  $ ~/.local/bin/elm2nix convert > elm-srcs.nix
+  $ nix-build
+
+## FAQ
+
+Q: Why are there no Nix expressions yet to install elm2nix?
+A: Waiting on https://github.com/input-output-hk/stack2nix 0.2 release
+
+Q: Why is mkDerivation inlined into `default.nix`?
+A: As it's considered unstable, it's generated for now. Might change in the future.

Setup.hs

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+import Distribution.Simple
+main = defaultMain

data/default.nix

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+{ nixpkgs ? <nixpkgs>
+, config ? {} }:
+
+with (import nixpkgs config);
+
+let
+  mkDerivation =
+    { srcs ? ./elm-srcs.nix
+    , exactDependencies ? ./elm-stuff/exact-dependencies.json
+    , src
+    , name
+    }:
+    let
+      sources = import srcs { inherit fetchzip; };
+    in  stdenv.mkDerivation {
+      inherit name src;
+
+      buildInputs = [ elmPackages.elm ];
+
+      preConfigurePhases = ["setupElmStuffPhase"];
+
+      setupElmStuffPhase = ''
+        runHook preSetupElmStuffPhase
+
+        rm -rf elm-stuff
+        mkdir elm-stuff
+        ln -s \${exactDependencies} elm-stuff/exact-dependencies.json
+
+        \${lib.concatStrings (lib.mapAttrsToList (name: src: ''
+          mkdir -p elm-stuff/packages/\${name}
+          ln -s \${src} elm-stuff/packages/\${name}/\${src.meta.version}
+        '') sources)}
+
+        runHook postSetupElmStuffPhase
+      '';
+
+      buildPhase = ''
+        mkdir -p $out/share/doc
+        elm make --warn --output $out/$name.js --docs $out/share/doc/$name.json
+      '';
+
+      installPhase = ":";
+    };
+in mkDerivation {
+  name = "${name}";
+  srcs = ./elm-srcs.nix;
+  src = ./.;
+}

elm2nix/Main.hs

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+{-# LANGUAGE QuasiQuotes #-}
+module Main where
+
+import Data.Semigroup ((<>))
+import qualified Control.Monad (join)
+import Data.Version (showVersion)
+import Data.String.Here
+import Options.Applicative
+import qualified Lib as Lib
+import qualified Paths_elm2nix as This
+import qualified Text.PrettyPrint.ANSI.Leijen as PP
+
+main :: IO ()
+main = do
+  cmd <- getOpts
+  case cmd of
+    Convert -> Lib.convert
+    Init -> Lib.init'
+
+getOpts :: IO Command
+getOpts = customExecParser p (infoH opts rest)
+  where
+    rest = fullDesc
+      <> progDesc "Convert Elm project to Nix expressions"
+      <> header ("elm2nix " ++ (showVersion This.version))
+      <> footerDoc (Just $ PP.string exampleText)
+    p = prefs showHelpOnEmpty
+
+exampleText :: String
+exampleText = [hereLit|
+
+Usage:
+
+  $ elm2nix init > default.nix
+  $ elm2nix convert > elm-srcs.nix
+  $ nix-build
+
+  Note: You have to run elm2nix from top-level directory of an Elm project.
+|]
+
+convertExample :: String
+convertExample = [hereLit|
+
+Steps:
+
+1) resolves `elm-package.json` into pinned `elm-stuff/exact-dependencies.json`
+2) converts `elm-stuff/exact-dependencies.json` into Nix expressions by using `nix-prefetch-url`
+
+|]
+
+opts :: Parser Command
+opts = subparser
+  ( command "init" (infoH (pure Init) (progDesc "Print default.nix to stdout"))
+ <> command "convert"  (infoH (pure Convert) (progDesc "Generate Nix expressions for Elm sources" <> footerDoc (Just $ PP.string convertExample))) )
+
+infoH a = info (helper <*> a)
+
+data Command
+  = Init
+  | Convert

src/Lib.hs

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+{-# LANGUAGE QuasiQuotes #-}
+
+module Lib
+    ( convert
+    , init'
+    ) where
+
+import Control.Monad (mapM)
+import Control.Monad.Except (liftIO, throwError)
+import Data.List (intercalate)
+import System.Directory (createDirectoryIfMissing, doesFileExist)
+import System.Exit (exitFailure)
+import System.IO ( hPutStrLn, stdout, stderr)
+import qualified Data.Map as Map
+import Data.String.Here
+
+import qualified Install.Solver as Solver
+import qualified Reporting.Error as Error
+import qualified Install.Plan as Plan
+import qualified Reporting.Error as Error
+import qualified Manager
+import qualified Install
+import qualified Elm.Package as Package
+import qualified Elm.Package.Description as Desc
+import qualified Elm.Package.Paths as Path
+import qualified Elm.Package.Solution as Solution
+
+import Prefetch
+
+-- CMDs
+
+convert :: IO ()
+convert = runCLI solveDependencies
+
+
+init' :: IO ()
+init' = runCLI generateDefault
+
+-- Utils
+
+runCLI f = do
+  result <- Manager.run f
+  case result of
+        Right () ->
+          return ()
+
+        Left err -> do
+          Error.toStderr err
+          exitFailure
+
+generateDefault :: Manager.Manager ()
+generateDefault = do
+  desc <- readDescription
+  let defaultNix = [template|data/default.nix|]
+      name = Package.toUrl (Desc.name desc) ++ "-" ++ show (Desc.version desc)
+  liftIO $ hPutStrLn stdout defaultNix
+
+solveDependencies :: Manager.Manager ()
+solveDependencies = do
+  liftIO $ hPutStrLn stderr $ "Resolving elm-package.json dependencies into elm-stuff/exact-dependencies.json ..."
+
+  desc <- readDescription
+  newSolution <- Solver.solve (Desc.elmVersion desc) (Desc.dependencies desc)
+  liftIO (createDirectoryIfMissing True Path.stuffDirectory)
+  liftIO (Solution.write Path.solvedDependencies newSolution)
+
+  liftIO $ hPutStrLn stderr $ "Prefetching tarballs and computing sha256 hashes ..."
+
+  let solL = Map.toList newSolution
+  sources <- liftIO $ mapM Prefetch.prefetchURL solL
+
+  liftIO $ hPutStrLn stdout $ generateNixSources sources
+
+readDescription :: Manager.Manager Desc.Description
+readDescription = do
+  exists <- liftIO (doesFileExist Path.description)
+
+  desc <-
+    if exists
+    then
+      Desc.read Error.CorruptDescription Path.description
+    else
+      Install.initialDescription
+  return desc
+
+
+generateNixSource :: DerivationSource -> String
+generateNixSource ds =
+   -- TODO: pass name to fetchzip
+   [iTrim|
+   "${Package.toUrl (drvName ds)}" = fetchzip {
+     url = "${drvUrl ds}";
+     sha256 = "${drvHash ds}";
+     meta = {
+       version = "${drvVersion ds}";
+     };
+   };
+   |]
+
+generateNixSources :: [DerivationSource] -> String
+generateNixSources dss =
+  [iTrim|
+  { fetchzip  }: {
+    ${intercalate "\n" (map generateNixSource dss)}
+}
+  |]

src/Prefetch.hs

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+-- Partially taken from cabal2nix/src/Distribution/Nixpkgs/Fetch.hs
+
+module Prefetch where
+
+import System.Environment
+import System.Exit
+import System.Process
+import qualified Data.ByteString.Lazy.Char8 as BS
+
+import qualified Elm.Package as Package
+
+
+data DerivationSource = DerivationSource
+  { drvHash :: String -- ^ Computed sha256 hash
+  , drvPath :: String -- ^ Nix store path of the derivation
+  , drvUrl :: String
+  , drvName :: Package.Name
+  , drvVersion :: Package.Version
+  } deriving (Show, Eq)
+
+instance Show Package.Version where
+  show ver = Package.versionToString ver
+
+-- | Use nix-prefetch-url to obtain resulting path and it's hash
+prefetchURL :: (Package.Name, Package.Version) -> IO DerivationSource
+prefetchURL (name, version) =
+  let
+    url = toZipballUrl name version
+    args :: [String]
+    args = ["--unpack", "--print-path", url]
+  in do
+  envs <- getEnvironment
+  (Nothing, Just stdoutH, _, processH) <- createProcess (proc "nix-prefetch-url" args)
+    { env = Nothing
+    , std_in = Inherit
+    , std_err = Inherit
+    , std_out = CreatePipe
+    }
+
+  exitCode <- waitForProcess processH
+  case exitCode of
+    ExitFailure _ -> error "nix-prefetch-url exited with non-zero"
+    ExitSuccess   -> do
+      buf <- BS.hGetContents stdoutH
+      let ls = BS.lines buf
+      case length ls of
+        0 -> error "unknown nix-prefetch-url output"
+        2 -> return $
+           DerivationSource
+             (BS.unpack $ head ls)
+             (BS.unpack $ head $ tail ls)
+             url
+             name
+             version
+        _ -> error "unknown nix-prefetch-url output"
+
+
+toZipballUrl :: Package.Name -> Package.Version -> String
+toZipballUrl name version =
+  "https://github.com/" ++ Package.toUrl name
+  ++ "/archive/" ++ Package.versionToString version ++ ".zip"

stack.yaml

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+resolver: lts-7.24
+packages:
+- .
+- location:
+    git: https://github.com/domenkozar/elm-package.git
+    commit: 2a5d2de0b55d4c9a30bec71f1cc6ff80130d7dfe
+  extra-dep: true
+- location:
+    git: https://github.com/elm-lang/elm-compiler.git
+    commit: 7ee7742a16188df7ff498ec4ef9f8b49e58a35fe
+  extra-dep: true
+
+extra-deps:
+  - http-types-0.8.6
+  - aeson-pretty-0.7.2
+  - containers-0.5.10.2
+  - binary-0.7.6.1
+  - optparse-applicative-0.13.2.0
+
+flags: {}
+
+nix:
+  enable: true
+  pure: false
+  packages: [zlib,haskellPackages.happy]

test/Spec.hs

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+main :: IO ()
+main = putStrLn "Test suite not yet implemented"