add shell for preparing dev tooling and generate purs-packages.nix

packages.dhall

-{-
-Welcome to Spacchetti local packages!
-
-Below are instructions for how to edit this file for most use
-cases, so that you don't need to know Dhall to use it.
-
-## Warning: Don't Move This Top-Level Comment!
-
-Due to how `dhall format` currently works, this comment's
-instructions cannot appear near corresponding sections below
-because `dhall format` will delete the comment. However,
-it will not delete a top-level comment like this one.
-
-## Use Cases
-
-Most will want to do one or both of these options:
-1. Override/Patch a package's dependency
-2. Add a package not already in the default package set
-
-This file will continue to work whether you use one or both options.
-Instructions for each option are explained below.
-
-### Overriding/Patching a package
-
-Purpose:
-- Change a package's dependency to a newer/older release than the
-    default package set's release
-- Use your own modified version of some dependency that may
-    include new API, changed API, removed API by
-    using your custom git repo of the library rather than
-    the package set's repo
-
-Syntax:
-Replace the overrides' "{=}" (an empty record) with the following idea
-The "//" or "⫽" means "merge these two records and
-  when they have the same value, use the one on the right:"
--------------------------------
-let override =
-  { packageName =
-      upstream.packageName ⫽ { updateEntity1 = "new value", updateEntity2 = "new value" }
-  , packageName =
-      upstream.packageName ⫽ { version = "v4.0.0" }
-  , packageName =
-      upstream.packageName // { repo = "https://www.example.com/path/to/new/repo.git" }
-  }
--------------------------------
-
-Example:
--------------------------------
-let overrides =
-  { halogen =
-      upstream.halogen ⫽ { version = "master" }
-  , halogen-vdom =
-      upstream.halogen-vdom ⫽ { version = "v4.0.0" }
-  }
--------------------------------
-
-### Additions
-
-Purpose:
-- Add packages that aren't alread included in the default package set
-
-Syntax:
-Replace the additions' "{=}" (an empty record) with the following idea:
--------------------------------
-let additions =
-  { "package-name" =
-       mkPackage
-         [ "dependency1"
-         , "dependency2"
-         ]
-         "https://example.com/path/to/git/repo.git"
-         "tag ('v4.0.0') or branch ('master')"
-  , "package-name" =
-       mkPackage
-         [ "dependency1"
-         , "dependency2"
-         ]
-         "https://example.com/path/to/git/repo.git"
-         "tag ('v4.0.0') or branch ('master')"
-  , etc.
-  }
--------------------------------
-
-Example:
--------------------------------
-let additions =
-  { benchotron =
-      mkPackage
-        [ "arrays"
-        , "exists"
-        , "profunctor"
-        , "strings"
-        , "quickcheck"
-        , "lcg"
-        , "transformers"
-        , "foldable-traversable"
-        , "exceptions"
-        , "node-fs"
-        , "node-buffer"
-        , "node-readline"
-        , "datetime"
-        , "now"
-        ]
-        "https://github.com/hdgarrood/purescript-benchotron.git"
-        "v7.0.0"
-  }
--------------------------------
--}
-
 let mkPackage =
       https://raw.githubusercontent.com/purescript/package-sets/psc-0.13.2-20190804/src/mkPackage.dhall sha256:0b197efa1d397ace6eb46b243ff2d73a3da5638d8d0ac8473e8e4a8fc528cf57
 
 let upstream =
-      https://raw.githubusercontent.com/purescript/package-sets/psc-0.13.2-20190804/src/packages.dhall sha256:2230fc547841b54bca815eb0058414aa03ed7b675042f8b3dda644e1952824e5
+      https://github.com/purescript/package-sets/releases/download/psc-0.13.2-20190804/packages.dhall sha256:2230fc547841b54bca815eb0058414aa03ed7b675042f8b3dda644e1952824e5
 
 let overrides =
       { thermite =
@@ -125,13 +15,11 @@ let overrides =
             , "react"
             , "react-dom"
             ]
-          "https://github.com/np/purescript-thermite.git"
-          "hide"
+            "https://github.com/poorscript/purescript-thermite.git"
+            "hide-2020-03-04"
       , globals =
           mkPackage
-          [ "functions"
-          , "maybe"
-          ]
+            [ "functions", "maybe" ]
             "https://github.com/purescript/purescript-globals"
             "v4.1.0"
       }
@@ -194,24 +82,18 @@ let additions =
       , markdown =
           mkPackage
             [ "precise" ]
-          {- "https://github.com/slamdata/purescript-markdown"
-          "v12.0.0" -}
             "https://github.com/poorscript/purescript-markdown"
-          "master"
+            "2020-03-04"
       , markdown-smolder =
           mkPackage
-          [ "markdown"
-          , "smolder" ]
-          {- "https://github.com/hgiasac/purescript-markdown-smolder"
-          "v2.0.1" -}
+            [ "markdown", "smolder" ]
             "https://github.com/poorscript/purescript-markdown-smolder"
-          "master"
+            "2020-03-04"
       , precise =
           mkPackage
             [ "prelude" ]
             "https://github.com/purescript-contrib/purescript-precise"
-          {- "v3.0.1" -}
-          "master"
+            "v4.0.0"
       , reactix =
           mkPackage
             [ "aff"
@@ -248,9 +130,11 @@ let additions =
             ]
             "https://github.com/slamdata/purescript-uri"
             "v7.0.0"
-       , read = mkPackage ["prelude", "maybe", "strings"]
+      , read =
+          mkPackage
+            [ "prelude", "maybe", "strings" ]
             "https://github.com/truqu/purescript-read"
             "v1.0.1"
       }
 
-in  upstream // overrides // additions
+in  upstream ⫽ overrides ⫽ additions

pinned.nix

+import (
+  builtins.fetchTarball {
+    url = "https://github.com/nixos/nixpkgs/archive/ece829033b7b8f4e81261fef5427144df4147bc4.tar.gz";
+    sha256 = "07n91k3d9i9pym8npsszha9mnvg4d1r0l0ldnhk4g8sx15vv1br5";
+  }
+)

shell.nix

+{ pkgs ? import ./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;
+  };
+
+  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
+    ${builtins.toString (builtins.map cpPackage (builtins.attrValues purs-packages))}
+    echo done installing deps.
+  '';
+
+  build-purs = pkgs.writeShellScriptBin "build-purs" ''
+    #!/usr/bin/env bash
+    purs compile "src/**/*.purs" ".psc-package/*/*/*/src/**/*.purs"
+  '';
+
+  storePath = x: ''"${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))}
+  '';
+in
+pkgs.mkShell {
+  buildInputs = [
+    easy-ps.purs
+    easy-ps.psc-package
+    soba
+    install-purs-packages
+    build-purs
+    build-purs-from-store
+    pkgs.yarn
+  ];
+}
+
+## 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`.
+#
+# 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
+