use psc-package-nix for project nix building

* uses scripts in ./nix/ to generate packages.json and purs-packages.nix
* build-purs now builds with dependencies in nix store
* PURS_IDE_SOURCES set in nix shell, so those are directly usable from latest versions of purescript-langauge-server and psc-ide-emacs
* regular psc-package usage is still supported

nix/easy-ps.nix

+{ pkgs ? import ./pinned.nix { } }:
+
+import
+  (
+    pkgs.fetchFromGitHub {
+      owner = "justinwoo";
+      repo = "easy-purescript-nix";
+      rev = "14e7d85431e9f9838d7107d18cb79c7fa534f54e";
+      sha256 = "0lmkppidmhnayv0919990ifdd61f9d23dzjzr8amz7hjgc74yxs0";
+    }
+  ) {
+  inherit pkgs;
+}

nix/generate-packages-json.nix

+#!/usr/bin/env nix-shell
+#!nix-shell ./generate-packages-json.nix --run 'exit'
+{ pkgs ? import ./pinned.nix { } }:
+let
+  easy-dhall = import (
+    pkgs.fetchFromGitHub {
+      owner = "justinwoo";
+      repo = "easy-dhall-nix";
+      rev = "288ee825c326f352a5db194a024bd3e1f2f735b2";
+      sha256 = "12v4ql1nm1famz8r80k1xkkdgj7285vy2vn16iili0qwvz3i98ah";
+    }
+  ) {
+    inherit pkgs;
+  };
+in
+pkgs.mkShell {
+  buildInputs = [ easy-dhall.dhall-simple easy-dhall.dhall-json-simple ];
+
+  shellHook = ''
+    dhall-to-json --file packages.dhall --output ./.psc-package/local/.set/packages.json
+    echo "generated packages.json"
+  '';
+}

nix/generate-purs-packages.nix

+#!/usr/bin/env nix-shell
+#!nix-shell ./generate-purs-packages.nix --run 'exit'
+{ pkgs ? import ./pinned.nix { } }:
+let
+  psc-package-nix = import ./psc-package-nix.nix { inherit pkgs; };
+  purs-project = import ./purs-project.nix { inherit pkgs; };
+  generatePursPackages = import "${psc-package-nix}/nix/generate-purs-packages.nix" {
+    inherit pkgs;
+    inherit (purs-project) packagesJson inputNames;
+  };
+in
+pkgs.mkShell {
+  buildInputs = [ generatePursPackages ];
+
+  shellHook = ''
+    generate-purs-packages > ./nix/purs-packages.nix
+    echo "generated purs-packages.nix"
+  '';
+}

nix/psc-package-nix.nix

+{ pkgs ? import ./pinned.nix { } }:
+
+pkgs.fetchFromGitHub {
+  owner = "justinwoo";
+  repo = "psc-package-nix";
+  rev = "0f1f001e2ea17ad461871a1873050f6aef5f1284";
+  sha256 = "0gbwcvw8rvxhlg9p6avd0812y263jzim1sra5frbdi0s6q0ngsgi";
+}

nix/purs-project.nix

+#!/usr/bin/env nix-shell
+{ pkgs ? import ./pinned.nix { } }:
+let
+  packagesJson = ../.psc-package/local/.set/packages.json;
+  inputNames = (pkgs.lib.importJSON ../psc-package.json).depends;
+  pursPackages = import ./purs-packages.nix { inherit pkgs; };
+  getUnquotedSourceGlob = x: ''${x.src}/src/**/*.purs'';
+  unquotedSourceGlobs = map getUnquotedSourceGlob (builtins.attrValues pursPackages);
+  quote = x: ''"${x}"'';
+  sourceGlobs = map quote unquotedSourceGlobs;
+in
+{
+  inherit packagesJson inputNames sourceGlobs unquotedSourceGlobs;
+}

shell.nix

-{ pkgs ? import ./pinned.nix {} }:
+{ pkgs ? import ./nix/pinned.nix {} }:
 let
-  easy-ps = import (
-    pkgs.fetchFromGitHub {
-      owner = "justinwoo";
-      repo = "easy-purescript-nix";
-      rev = "14e7d85431e9f9838d7107d18cb79c7fa534f54e";
-      sha256 = "0lmkppidmhnayv0919990ifdd61f9d23dzjzr8amz7hjgc74yxs0";
-    }
-  ) {
-    inherit pkgs;
-  };
-
-  soba = import (
-    pkgs.fetchFromGitHub {
-      owner = "justinwoo";
-      repo = "soba";
-      rev = "2add8804bce7e7c1ab5eb1c3d8f6783e938a04d3";
-      sha256 = "1qagyklcllr2sxdb315prw33af6g37762zgk2ahh3ifxpns6ifxx";
-    }
-  ) {
-    inherit pkgs;
-  };
+  easy-ps = import ./nix/easy-ps.nix { inherit pkgs; };
 
   purs-packages = import ./purs-packages.nix { inherit pkgs; };
 
-  cpPackage = pp:
-    let
-      target = ".psc-package/local/${pp.name}/${pp.version}";
-    in
-      ''
-        mkdir -p ${target}
-        cp --no-preserve=mode,ownership,timestamp -r ${pp.fetched.outPath}/* ${target}
-      '';
-
-  install-purs-packages = pkgs.writeShellScriptBin "install-purs-packages" ''
-    #!/usr/bin/env bash
-    ${builtins.toString (builtins.map cpPackage (builtins.attrValues purs-packages))}
-    echo done installing deps.
-  '';
+  purs-project = import ./nix/purs-project.nix { inherit pkgs; };
 
   build-purs = pkgs.writeShellScriptBin "build-purs" ''
     #!/usr/bin/env bash
-    purs compile "src/**/*.purs" ".psc-package/*/*/*/src/**/*.purs"
-  '';
-
-  storePath = x: ''"${x.fetched.outPath}/src/**/*.purs"'';
-
-  build-purs-from-store = pkgs.writeShellScriptBin "build-purs-from-store" ''
-    #!/usr/bin/env bash
-    purs compile "src/**/*.purs" \
-      ${builtins.toString (builtins.map storePath (builtins.attrValues purs-packages))}
+    purs compile ${toString purs-project.sourceGlobs} "src/**/*.purs" "test/**/*.purs"
   '';
 
   build = pkgs.writeShellScriptBin "build" ''
@@ -72,28 +31,28 @@ pkgs.mkShell {
   buildInputs = [
     easy-ps.purs
     easy-ps.psc-package
-    soba
-    install-purs-packages
     build-purs
-    build-purs-from-store
     build
     repl
     pkgs.yarn
   ];
+
+  shellHook = ''
+    export PURS_IDE_SOURCES='${toString purs-project.unquotedSourceGlobs}'
+  '';
 }
 
 ## how to build the project with nix dependencies:
 #
 # 1. start a nix shell (e.g. `nix-shell -j 20`, this uses 20 jobs to fetch deps)
 # 2. run `yarn` to install npm deps
-# 3. run `install-purs-packages` if you want dependencies locally, available for psc-package and for inspection
-# 4. run `build-purs` to build from local sources. otherwise use `build-purs-from-store`.
+# 3a. run `build-purs` to build using nix store dependencies, and make sure to update your purescript ide tooling as necesssary
+# 3b. or simply use `psc-package` as you might want to anyway
 #
 # note that the purescript compiler uses filepaths and timestamps, so using the above two commands
 # interchangeably will lead to constant rebuilding of the entire project.
 #
 ## how to update purs-packages.nix
 #
-# 1. run `soba insdhall` to generate packages.json
-# 2. run `soba nix` to generate a nix derivation from packages.json
-
+# 1. run `nix/generate-packages-json.nix` to generate packages.json
+# 2. run `nix/generate-purs-packages.nix` to generate purs-packages.nix