added nix flake

cmark.nix

@@ -0,0 +1,22 @@
+{ buildLuarocksPackage, fetchFromGitHub, fetchurl }:
+buildLuarocksPackage {
+  pname = "cmark";
+  version = "0.30.2-1";
+  knownRockspec = (fetchurl {
+    url = "mirror://luarocks/cmark-0.30.2-1.rockspec";
+    sha256 = "077kvl9xa9yj0fxyyxxw43k9v9dgd5f11ax8hhxj3nx8vfs5rps8";
+  }).outPath;
+  src = fetchFromGitHub {
+    owner = "jgm";
+    repo = "cmark-lua";
+    rev = "0.30.2";
+    hash = "sha256-6Bzq0FdyqXXiL6pLDRFbULFJpowF0P6CvAw8iqFXkkQ=";
+  };
+
+  meta = {
+    homepage = "https://github.com/jgm/cmark-lua";
+    description = "Lua wrapper for libcmark, CommonMark Markdown parsing\
+      and rendering library";
+    license.fullName = "BSD2";
+  };
+}

flake.lock

@@ -0,0 +1,27 @@
+{
+  "nodes": {
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1721562059,
+        "narHash": "sha256-Tybxt65eyOARf285hMHIJ2uul8SULjFZbT9ZaEeUnP8=",
+        "owner": "nixos",
+        "repo": "nixpkgs",
+        "rev": "68c9ed8bbed9dfce253cc91560bf9043297ef2fe",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nixos",
+        "ref": "nixos-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "nixpkgs": "nixpkgs"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}

flake.nix

@@ -0,0 +1,30 @@
+{
+  inputs = {
+    nixpkgs.url = "github:nixos/nixpkgs/nixos-unstable";
+  };
+
+  outputs = { self, nixpkgs, ... } @ inputs:
+    let
+      pkgs = nixpkgs.legacyPackages.x86_64-linux;
+    in
+    {
+      devShells.x86_64-linux.default = pkgs.mkShell {
+        buildInputs = [
+          (pkgs.lua5_1.withPackages (ps: with ps; [
+            (
+              let
+                buildLuarocksPackage = ps.buildLuarocksPackage;
+              in
+              pkgs.callPackage ./cmark.nix {
+                inherit buildLuarocksPackage;
+              }
+            )
+            luafilesystem
+            luasocket
+            luasec
+            fennel
+          ]))
+        ];
+      };
+    };
+}