Make repository a nix flake

Make git-email.el a nix flake for an easier installation process for
Nix users.  It currently exposes two packages:

- git-email-full -- This includes all the optional libraries
- git-email -- This only includes the core `git-email.el` library

They both get the source from directory from the git repository,
meaning they will get updates as soon as a commit is made.

* default.nix: Add file.
* flake.lock: Add file.
* flake.nix: Add file.

3 files changed, 89 insertions, 0 deletions

diff --git a/default.nix b/default.nix
new file mode 100644
index 0000000..9fa551a
--- /dev/null
+++ b/default.nix
@@ -0,0 +1,29 @@
+{ lib, nix-gitignore, emacsPackages }:
+let
+  inherit (emacsPackages) trivialBuild;
+  flakeRoot = toString ../.;
+in
+lib.recurseIntoAttrs rec {
+
+  git-email-full = trivialBuild rec {
+    pname = "git-email-full";
+    version = "git";
+    src = nix-gitignore.gitignoreSource (flakeRoot + ".gitignore") ./.;
+    packageRequires = with emacsPackages; [
+      magit
+      transient
+      notmuch
+    ];
+  };
+
+  git-email = trivialBuild rec {
+    pname = "git-email";
+    version = "git";
+    src = builtins.filterSource
+      (path: type:
+        baseNameOf path != "git-email-magit.el" &&
+        baseNameOf path != "git-email-notmuch.el" &&
+        baseNameOf path != "git-email-gnus.el"
+      ) ./.;
+  };
+}
diff --git a/flake.lock b/flake.lock
new file mode 100644
index 0000000..52c007e
--- /dev/null
+++ b/flake.lock
@@ -0,0 +1,43 @@
+{
+  "nodes": {
+    "flake-utils": {
+      "locked": {
+        "lastModified": 1610051610,
+        "narHash": "sha256-U9rPz/usA1/Aohhk7Cmc2gBrEEKRzcW4nwPWMPwja4Y=",
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "rev": "3982c9903e93927c2164caa727cd3f6a0e6d14cc",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "type": "github"
+      }
+    },
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1612407036,
+        "narHash": "sha256-3wFGXSK9tQU/6dPfwjNUxygeZCbYxe0O0JXVyj1G2tk=",
+        "owner": "nixos",
+        "repo": "nixpkgs",
+        "rev": "04d5f1e3a87d413181af5d6dd68568228addf1c3",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nixos",
+        "ref": "nixpkgs-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "flake-utils": "flake-utils",
+        "nixpkgs": "nixpkgs"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}
diff --git a/flake.nix b/flake.nix
new file mode 100644
index 0000000..176f27e
--- /dev/null
+++ b/flake.nix
@@ -0,0 +1,17 @@
+{
+  description = "git-email.el flake";
+
+  inputs = {
+    nixpkgs.url = "github:nixos/nixpkgs/nixpkgs-unstable";
+    flake-utils.url = "github:numtide/flake-utils";
+  };
+
+  outputs = { self, nixpkgs, flake-utils }:
+    flake-utils.lib.eachDefaultSystem (system:
+      let pkgs = nixpkgs.legacyPackages.${system};
+      in
+      rec {
+        packages = pkgs.lib.recurseIntoAttrs (pkgs.callPackage ./. {});
+        defaultPackage = packages.git-email-full;
+      });
+}