Add common/lib.nix

common/lib.nix

@@ -0,0 +1,43 @@
+let
+  pkgs = import <nixpkgs> {};
+  unstable = import <unstable> {};
+  shh = unstable.haskell.lib.overrideCabal unstable.haskellPackages.shh (drv: {
+    broken = false;
+    doCheck = false;
+  });
+  writeHaskellScript = { name ? "haskell-script", bins ? [pkgs.coreutils], libraries ? [], imports ? []}: code:
+    unstable.writers.writeHaskellBin name { libraries = libraries ++ [shh]; } ''
+      {-# LANGUAGE DeriveDataTypeable #-}
+      {-# LANGUAGE TemplateHaskell #-}
+      import Shh
+      ${builtins.concatStringsSep "\n" (map (x: "import ${x}") imports)}
+
+      -- Load binaries from Nix packages. The dependencies will be captured
+      -- in the closure.
+      loadFromBins ["${builtins.concatStringsSep ''", "'' (builtins.map toString bins)}"]
+
+      ${code}
+    '';
+in {
+    inherit writeHaskellScript;
+    getNivPath = writeHaskellScript {
+      name = "get-niv-path";
+      bins = [pkgs.nix pkgs.coreutils];
+      imports = ["System.Console.CmdArgs.Implicit" "Data.Text.Lazy" "Data.Text.Lazy.Encoding"];
+      libraries = [ unstable.haskellPackages.cmdargs unstable.haskellPackages.text ];
+    } ''
+
+      data Path = Path {
+        sources :: String,
+        channel :: String
+      } deriving (Show, Data, Typeable)
+
+      path = Path{ sources = def &= argPos 0, channel = def &= argPos 1}
+
+      main :: IO ()
+      main = do
+            path <- cmdArgs path
+            path <- readTrim $ nix_instantiate "--eval" "-E" ("toString (import " ++ sources path ++ ")." ++ channel path)
+            echo . unpack . dropAround ('"' ==) $ decodeUtf8 path
+      '';
+}

home-manager/default.nix

@@ -1,6 +1,6 @@
 { pkgs, config, ... }:
 let
-  inherit (import ../nix/my-lib.nix) writeHaskellScript getNivPath;
+  inherit (import ../common/my-lib.nix) writeHaskellScript getNivPath;
   sources = import ../nix/sources.nix;
   inherit (config.m-0.private) me meWork;
   configPath = "/home/${config.home.username}/git/nixos/config";

nix/sources.json

@@ -0,0 +1,50 @@
+{
+    "home-manager": {
+        "branch": "release-19.03",
+        "description": "Manage a user environment using Nix",
+        "homepage": "",
+        "owner": "rycee",
+        "repo": "home-manager",
+        "rev": "4f13f06b016d59420cafe34915abdd6b795d3416",
+        "sha256": "1chl04jimba1n1r4cqaq66kry4fy2xgsdgbqcl3rkw4ykd5yfcsc",
+        "type": "tarball",
+        "url": "https://github.com/rycee/home-manager/archive/4f13f06b016d59420cafe34915abdd6b795d3416.tar.gz",
+        "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
+    },
+    "niv": {
+        "branch": "master",
+        "description": "Easy dependency management for Nix projects",
+        "homepage": "https://github.com/nmattia/niv",
+        "owner": "nmattia",
+        "repo": "niv",
+        "rev": "8b7b70465c130d8d7a98fba1396ad1481daee518",
+        "sha256": "0fgdrxn2vzpnzr6pxaiyn5zzbd812c6f7xjjhfir0kpzamjnxwwl",
+        "type": "tarball",
+        "url": "https://github.com/nmattia/niv/archive/8b7b70465c130d8d7a98fba1396ad1481daee518.tar.gz",
+        "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
+    },
+    "nixpkgs": {
+        "branch": "nixos-19.03",
+        "description": "Nixpkgs/NixOS branches that track the Nixpkgs/NixOS channels",
+        "homepage": null,
+        "owner": "NixOS",
+        "repo": "nixpkgs-channels",
+        "rev": "55b8860aa209e987f6f15c523811e4861d97d6af",
+        "sha256": "0ri58704vwv6gnyw33vjirgnvh2f1201vbflk0ydj5ff7vpyy7hf",
+        "type": "tarball",
+        "url": "https://github.com/NixOS/nixpkgs-channels/archive/55b8860aa209e987f6f15c523811e4861d97d6af.tar.gz",
+        "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
+    },
+    "unstable": {
+        "branch": "nixos-unstable",
+        "description": "Nixpkgs/NixOS branches that track the Nixpkgs/NixOS channels",
+        "homepage": null,
+        "owner": "NixOS",
+        "repo": "nixpkgs-channels",
+        "rev": "362be9608c3e0dc5216e9d1d5f5c1a5643b7f7b1",
+        "sha256": "0934rhanamsnhawg15gg6cy9ird3c47hsqn5s46lq2n5kzl6v7ly",
+        "type": "tarball",
+        "url": "https://github.com/NixOS/nixpkgs-channels/archive/362be9608c3e0dc5216e9d1d5f5c1a5643b7f7b1.tar.gz",
+        "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
+    }
+}

nix/sources.nix

@@ -0,0 +1,89 @@
+# This file has been generated by Niv.
+
+# A record, from name to path, of the third-party packages
+with rec
+{
+  pkgs =
+    if hasNixpkgsPath
+    then
+        if hasThisAsNixpkgsPath
+        then import (builtins_fetchTarball { inherit (sources_nixpkgs) url sha256; }) {}
+        else import <nixpkgs> {}
+    else
+        import (builtins_fetchTarball { inherit (sources_nixpkgs) url sha256; }) {};
+
+  sources_nixpkgs =
+    if builtins.hasAttr "nixpkgs" sources
+    then sources.nixpkgs
+    else abort
+    ''
+        Please specify either <nixpkgs> (through -I or NIX_PATH=nixpkgs=...) or
+        add a package called "nixpkgs" to your sources.json.
+    '';
+
+  # fetchTarball version that is compatible between all the versions of Nix
+  builtins_fetchTarball =
+      { url, sha256 }@attrs:
+      let
+        inherit (builtins) lessThan nixVersion fetchTarball;
+      in
+        if lessThan nixVersion "1.12" then
+          fetchTarball { inherit url; }
+        else
+          fetchTarball attrs;
+
+  # fetchurl version that is compatible between all the versions of Nix
+  builtins_fetchurl =
+      { url, sha256 }@attrs:
+      let
+        inherit (builtins) lessThan nixVersion fetchurl;
+      in
+        if lessThan nixVersion "1.12" then
+          fetchurl { inherit url; }
+        else
+          fetchurl attrs;
+
+  # A wrapper around pkgs.fetchzip that has inspectable arguments,
+  # annoyingly this means we have to specify them
+  fetchzip = { url, sha256 }@attrs: pkgs.fetchzip attrs;
+
+  hasNixpkgsPath = (builtins.tryEval <nixpkgs>).success;
+  hasThisAsNixpkgsPath =
+    (builtins.tryEval <nixpkgs>).success && <nixpkgs> == ./.;
+
+  sources = builtins.fromJSON (builtins.readFile ./sources.json);
+
+  mapAttrs = builtins.mapAttrs or
+    (f: set: with builtins;
+      listToAttrs (map (attr: { name = attr; value = f attr set.${attr}; }) (attrNames set)));
+
+  # borrowed from nixpkgs
+  functionArgs = f: f.__functionArgs or (builtins.functionArgs f);
+  callFunctionWith = autoArgs: f: args:
+    let auto = builtins.intersectAttrs (functionArgs f) autoArgs;
+    in f (auto // args);
+
+  getFetcher = spec:
+    let fetcherName =
+      if builtins.hasAttr "type" spec
+      then builtins.getAttr "type" spec
+      else "builtin-tarball";
+    in builtins.getAttr fetcherName {
+      "tarball" = fetchzip;
+      "builtin-tarball" = builtins_fetchTarball;
+      "file" = pkgs.fetchurl;
+      "builtin-url" = builtins_fetchurl;
+    };
+};
+# NOTE: spec must _not_ have an "outPath" attribute
+mapAttrs (_: spec:
+  if builtins.hasAttr "outPath" spec
+  then abort
+    "The values in sources.json should not have an 'outPath' attribute"
+  else
+    if builtins.hasAttr "url" spec && builtins.hasAttr "sha256" spec
+    then
+      spec //
+      { outPath = callFunctionWith spec (getFetcher spec) { }; }
+    else spec
+  ) sources

system/default.nix

@@ -1,6 +1,6 @@
 { pkgs, config, lib,  ... }:
 let
-  inherit (import ../nix/my-lib.nix) writeHaskellScript getNivPath;
+  inherit (import ../common/my-lib.nix) writeHaskellScript getNivPath;
   me = config.m-0.private.me;
   sources = import ../nix/sources.nix;
   nixpkgsPath = sources.nixpkgs;