Package as flake

.gitignore

@@ -1,2 +1,3 @@
 /target
 /.envrc
+/result*

README.md

@@ -1,4 +1,4 @@
-nil: Language server of Nix Expression Language
+nil: Language server for Nix Expression Language
 
 🚧 *This project is under development, but be happy to try it out!*
 
@@ -19,8 +19,23 @@ Super fast incremental analysis! Scans `all-packages.nix` in less then 0.1s and
 
 ## Installation
 
-1. Have the latest stable version of Rust installed.
-2. `cargo install --git https://github.com/oxalica/nil.git`
+**TODO: Beginner friendly instructions.**
+
+This repo is packaged via [Nix flakes][nix-flakes], the language server binary package is
+available through the default flake output `github:oxalica/nil#` with the path `bin/nil`.
+
+Flake output structure:
+```
+├───devShells
+│   └───(...)
+└───packages
+    ├───x86_64-linux
+    │   ├───default: package 'nil-unstable-2022-08-04'
+    │   └───nil: package 'nil-unstable-2022-08-04'
+    └───(...)
+```
+
+[nix-flakes]: https://nixos.wiki/wiki/Flakes
 
 ### For neovim `nvim-lspconfig` user
 
@@ -30,8 +45,8 @@ Add the following vimscript to your configuration.
 lua <<EOF
   require('lspconfig').rnix.setup {
     autostart = true,
-    -- Set to the path to `nil` binary you installed.
-    cmd = { vim.env.HOME .. "/.local/bin/nil" },
+    -- Change it to the path to the `nil` binary you installed.
+    cmd = { "/run/current-system/sw/bin/bin/nil" },
   }
 EOF
 ```

flake.lock

@@ -0,0 +1,67 @@
+{
+  "nodes": {
+    "flake-utils": {
+      "locked": {
+        "lastModified": 1656928814,
+        "narHash": "sha256-RIFfgBuKz6Hp89yRr7+NR5tzIAbn52h8vT6vXkYjZoM=",
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "rev": "7e2a3b3dfd9af950a856d66b0a7d01e3c18aa249",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "type": "github"
+      }
+    },
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1659494082,
+        "narHash": "sha256-XRwMisQY/BcvDMDRVkd4n3/CT89HOtlPgWIQUNPvWSc=",
+        "owner": "nixos",
+        "repo": "nixpkgs",
+        "rev": "8c7576622aeb4707351a17e83429667f42e7d910",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nixos",
+        "ref": "nixpkgs-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "flake-utils": "flake-utils",
+        "nixpkgs": "nixpkgs",
+        "rust-overlay": "rust-overlay"
+      }
+    },
+    "rust-overlay": {
+      "inputs": {
+        "flake-utils": [
+          "flake-utils"
+        ],
+        "nixpkgs": [
+          "nixpkgs"
+        ]
+      },
+      "locked": {
+        "lastModified": 1659599305,
+        "narHash": "sha256-htzFq5RffyoKSZxiLfpUq5CyhkQwycsXB5ptale5e78=",
+        "owner": "oxalica",
+        "repo": "rust-overlay",
+        "rev": "28cedcb8dfea9f1b96b0635cf99fe6bdca163f4e",
+        "type": "github"
+      },
+      "original": {
+        "owner": "oxalica",
+        "repo": "rust-overlay",
+        "type": "github"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}

flake.nix

@@ -0,0 +1,48 @@
+{
+  description = "Language Server for Nix Expression Language";
+
+  inputs = {
+    flake-utils.url = "github:numtide/flake-utils";
+    nixpkgs.url = "github:nixos/nixpkgs/nixpkgs-unstable";
+    rust-overlay.url = "github:oxalica/rust-overlay";
+    rust-overlay.inputs.flake-utils.follows = "flake-utils";
+    rust-overlay.inputs.nixpkgs.follows = "nixpkgs";
+  };
+
+  outputs = { self, flake-utils, nixpkgs, rust-overlay }:
+    flake-utils.lib.eachDefaultSystem (system:
+      let
+        inherit (builtins) substring;
+        pkgs = nixpkgs.legacyPackages.${system};
+        rustPkgs = rust-overlay.packages.${system};
+      in {
+        packages = rec {
+          default = nil;
+          nil = pkgs.rustPlatform.buildRustPackage {
+            pname = "nil";
+            version = let mtime = self.lastModifiedDate; in
+              "unstable-${substring 0 4 mtime}-${substring 4 2 mtime}-${substring 6 2 mtime}";
+            src = ./.;
+            cargoLock.lockFile = ./Cargo.lock;
+            buildAndTestSubdir = "lsp";
+          };
+        };
+
+        devShells.default = pkgs.mkShell {
+          packages = [
+            # Override the stable rustfmt.
+            rustPkgs.rust-nightly_2022-08-01.availableComponents.rustfmt
+            rustPkgs.rust
+            pkgs.jq
+            (import ./neovim-env.nix { inherit pkgs; })
+          ];
+
+          RUST_BACKTRACE = 1;
+          NIXPKGS = nixpkgs;
+
+          shellHook = ''
+            export NIL_PATH="$(cargo metadata --format-version=1 | jq -r .target_directory)"
+          '';
+        };
+      });
+}

neovim-env.nix

@@ -95,8 +95,4 @@ let
   '';
 
 in
-pkgs.mkShell {
-  packages = [
-    neovim
-  ];
-}
+  neovim