Add support for Lean 4

README.md

@@ -189,6 +189,10 @@ A dev template that's fully customizable.
 - [tectonic]
 - [texlab]
 
+### [`lean4`](./lean4/)
+
+- [Lean] 4.9.0
+
 ### [`nickel`](./nickel/)
 
 - [Nickel] 0.2.0
@@ -372,6 +376,7 @@ All of the templates have only the root [flake](./flake.nix) as a flake input. T
 [knitr]: https://yihui.org/knitr
 [kotlin]: https://kotlinlang.org
 [latex]: https://latex-project.org
+[lean]: https://lean-lang.org
 [lcov]: https://ltp.sourceforge.net/coverage/lcov.php
 [leiningen]: https://leiningen.org
 [levant]: https://github.com/hashicorp/levant

flake.nix

@@ -183,6 +183,11 @@
           description = "LaTeX development environment";
         };
 
+        lean4 = {
+          path = ./lean4;
+          description = "Lean 4 development environment";
+        };
+
         nickel = {
           path = ./nickel;
           description = "Nickel development environment";

lean4/.envrc

@@ -0,0 +1 @@
+use flake

lean4/flake.nix

@@ -0,0 +1,20 @@
+{
+  description = "A Nix-flake-based Lean 4 development environment";
+
+  inputs.nixpkgs.url = "https://flakehub.com/f/NixOS/nixpkgs/0.1.*.tar.gz";
+
+  outputs = { self, nixpkgs }:
+    let
+      supportedSystems = [ "x86_64-linux" "aarch64-linux" "x86_64-darwin" "aarch64-darwin" ];
+      forEachSupportedSystem = f: nixpkgs.lib.genAttrs supportedSystems (system: f {
+        pkgs = import nixpkgs { inherit system; };
+      });
+    in
+    {
+      devShells = forEachSupportedSystem ({ pkgs }: {
+        default = pkgs.mkShell {
+          packages = with pkgs; [ lean4 ];
+        };
+      });
+    };
+}