feat: add nix(os) packaging &development support

* Adds `/flake.nix`, which allows the package to be installed & developed
  easily by most NixOS users.
* Adds `/default.nix`, which is an older way that some Nix(OS) users
  may expect software to be packaged.
* Adds `/nix/**/*.nix`, which defines various additional helpers used by
  `/flake.nix` and `/default.nix`.
* Updates `.gitignore` to include `/result`, which is the default output
  location when the package is built using

  `nix flake build .` or `nix-build .`

.gitignore

@@ -1 +1,2 @@
 /fennel-ls
+/result

README.md

@@ -17,6 +17,11 @@ make && make install PREFIX=$HOME # if you have ~/bin on your $PATH
 
 For now, the only way to install is to build from source, but I plan on adding fennel-ls to luarocks soon.
 
+### NixOS
+
+If you are using NixOS, you may use the included `/flake.nix` or `/default.nix`
+to to build the language server configure a development environment.
+
 ## Set Up Your Editor
 
 Once you've installed the binary somewhere on your computer, the next step is to set up your text editor! Each editor has a different way of doing it.

changelog.md

@@ -1,5 +1,6 @@
 # Changelog
 
+* Add [Nix(OS)](https://nixos.org) support
 * Fix bug with renaming vars
 * Improve multival tracking
 * `textEdit` field is present in completions

default.nix

@@ -0,0 +1 @@
+{ pkgs ? import <nixpkgs> {} }: pkgs.callPackage ./nix/package.nix {}

flake.lock

@@ -0,0 +1,57 @@
+{
+  "nodes": {
+    "flake-utils": {
+      "inputs": {
+        "systems": "systems"
+      },
+      "locked": {
+        "lastModified": 1705309234,
+        "narHash": "sha256-uNRRNRKmJyCRC/8y1RqBkqWBLM034y4qN7EprSdmgyA=",
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "rev": "1ef2e671c3b0c19053962c07dbda38332dcebf26",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "type": "github"
+      }
+    },
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 0,
+        "narHash": "sha256-S+S97c/HzkO2A/YsU7ZmNF9w2s7Xk6P8dzmfDdckzLs=",
+        "path": "/nix/store/sb3x0gk95v9h285ch8cdqv3gfjp97p1b-source",
+        "type": "path"
+      },
+      "original": {
+        "id": "nixpkgs",
+        "type": "indirect"
+      }
+    },
+    "root": {
+      "inputs": {
+        "flake-utils": "flake-utils",
+        "nixpkgs": "nixpkgs"
+      }
+    },
+    "systems": {
+      "locked": {
+        "lastModified": 1681028828,
+        "narHash": "sha256-Vy1rq5AaRuLzOxct8nz4T6wlgyUR7zLU309k9mBC768=",
+        "owner": "nix-systems",
+        "repo": "default",
+        "rev": "da67096a3b9bf56a91d16901293e51ba5b49a27e",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-systems",
+        "repo": "default",
+        "type": "github"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}

flake.nix

@@ -0,0 +1,38 @@
+{
+  description = "A language server for fennel";
+
+  inputs.flake-utils.url = "github:numtide/flake-utils";
+
+  outputs = { self, nixpkgs, flake-utils }:
+    flake-utils.lib.eachDefaultSystem (system:
+      let
+        pkgs = import nixpkgs { inherit system; };
+        inherit (flake-utils.lib) mkApp;
+        inherit (pkgs) callPackage;
+      in
+      {
+        packages = {
+          fennel_ls = callPackage ./nix/package.nix {
+            version = self.shortRev or self.shortDirtyRev or self.lastModifiedDate;
+          };
+          default = self.packages.${system}.fennel_ls;
+        };
+
+        devShells = {
+          fennel_ls = callPackage ./nix/shell.nix {
+            fennel_ls = self.packages.${system}.fennel_ls;
+          };
+
+          default = self.devShells.${system}.fennel_ls;
+        };
+
+        apps = rec {
+          fennel_ls = mkApp {
+            drv = self.packages.${system}.fennel_ls;
+            exePath = "/bin/fennel-ls";
+          };
+          default = self.apps.${system}.fennel_ls;
+        };
+      }
+    );
+}

nix/package.nix

@@ -0,0 +1,16 @@
+{ version ? "dirty"
+, stdenv
+, lua
+}: stdenv.mkDerivation {
+  pname = "fennel_ls";
+  inherit version;
+
+  src = ./..;
+
+  makeFlags = [ "PREFIX=$(out)" ];
+
+  buildInputs = [ lua ];
+
+  doCheck = true;
+
+}

nix/shell.nix

@@ -0,0 +1,7 @@
+{ callPackage
+, fennel_ls ? callPackage ./package.nix { }
+, mkShell
+}: mkShell {
+  buildInputs = fennel_ls.buildInputs or [ ];
+  nativeBuildInputs = fennel_ls.nativeBuildInputs or [ ];
+}