Add simple template

flake.nix

@@ -38,14 +38,22 @@
             } // attrs);
           in
             /*
-            You might read
-            https://nixos.org/manual/nixpkgs/stable/#sec-overlays-argument and
-            want to change this but because of how we're doing overlays we will
-            be overriding any extraOverlays if we don't use `appendOverlays`
+              You might read
+              https://nixos.org/manual/nixpkgs/stable/#sec-overlays-argument and
+              want to change this but because of how we're doing overlays we will
+              be overriding any extraOverlays if we don't use `appendOverlays`
             */
           pkgs.appendOverlays extraOverlays;
 
         overlays.default = final: prev: overlay final prev;
+
+        templates.simple = {
+          description =
+            "Simple setup for ocaml development";
+          path = ./templates/simple;
+        };
+
+        templates.default = self.templates.simple;
       }
       (flake-utils.lib.eachDefaultSystem (system: {
         legacyPackages = self.makePkgs { inherit system; };

templates/simple/.gitignore

@@ -0,0 +1,2 @@
+_build
+result

templates/simple/dune-project

@@ -0,0 +1 @@
+(lang dune 3.0)

templates/simple/flake.nix

@@ -0,0 +1,44 @@
+{
+  nixConfig = {
+    extra-substituters = "https://ocaml.nix-cache.com";
+    extra-trusted-public-keys = "ocaml.nix-cache.com-1:/xI2h2+56rwFfKyyFVbkJSeGqSIYMC/Je+7XXqGKDIY=";
+  };
+
+  inputs = {
+    nixpkgs.url = "github:nix-ocaml/nix-overlays";
+    flake-utils.url = "github:numtide/flake-utils";
+    flake-utils.follows = "nixpkgs/flake-utils";
+    nix-filter.url = "github:numtide/nix-filter";
+  };
+
+  outputs = { self, nixpkgs, flake-utils, nix-filter }:
+    flake-utils.lib.eachDefaultSystem (system:
+      let pkgs = nixpkgs.legacyPackages.${system}; in
+      {
+        packages = {
+          inherit (pkgs.ocamlPackages.callPackage ./nix {
+            inherit nix-filter;
+            doCheck = true;
+          }) package;
+        };
+
+        devShells = {
+          default = pkgs.mkShell {
+            inputsFrom = with self.packages.${system}; [
+              package
+            ];
+
+            nativeBuildInputs = with pkgs.ocamlPackages; [
+              ocaml
+              dune
+
+              ocaml-lsp
+
+              ocamlformat
+              dune-release
+              odoc
+            ];
+          };
+        };
+      });
+}

templates/simple/nix/default.nix

@@ -0,0 +1,49 @@
+{ pkgs
+, stdenv
+, lib
+, nix-filter
+, ocamlPackages
+, static ? false
+, doCheck
+}:
+with ocamlPackages; {
+  package = buildDunePackage {
+    pname = "package";
+    version = "1.0.0";
+
+    src = with nix-filter.lib;
+      filter {
+        # Root of the project relative to this file
+        root = ./..;
+        # If no include is passed, it will include all the paths.
+        include = [
+          # Include the "src" path relative to the root.
+          "src"
+          "test"
+          # Include this specific path. The path must be under the root.
+          ../package.opam
+          ../dune-project
+        ];
+      };
+
+    checkInputs = [
+      # Put test dependencies here
+      alcotest
+    ];
+
+    propagatedBuildInputs = [
+      # Put dependencies here if you're creating a library
+    ];
+
+    buildInputs = [
+      # Put build-time dependencies here
+    ];
+
+    inherit doCheck;
+
+    meta = {
+      description = "Describe your project here";
+      # license = stdenv.lib.licenses.bsd3;
+    };
+  };
+}

templates/simple/src/bin/dune

@@ -0,0 +1,4 @@
+(executable
+ (name main)
+ (public_name package)
+ (libraries package))

templates/simple/src/bin/main.ml

@@ -0,0 +1,18 @@
+let main () =
+  print_string "First number: ";
+  let first = read_line () |> int_of_string_opt in
+  print_string "Second number: ";
+  let second = read_line () |> int_of_string_opt in
+  let output =
+    match (first, second) with
+    | None, Some _ -> "First input is not a number"
+    | Some _, None -> "Second input is not a number"
+    | None, None -> "Neither of the inputs is a number"
+    | Some f, Some s ->
+        let number = Package.add f s in
+        Printf.sprintf "%i + %i = %i" f s number
+  in
+  print_endline output
+;;
+
+main ()

templates/simple/src/lib/dune

@@ -0,0 +1,3 @@
+(library
+ (name package)
+ (public_name package))

templates/simple/src/lib/package.ml

@@ -0,0 +1 @@
+let add a b = a + b

templates/simple/test/dune

@@ -0,0 +1,3 @@
+(test
+ (name test)
+ (libraries alcotest package))

templates/simple/test/test.ml

@@ -0,0 +1,5 @@
+let test_add () = Alcotest.(check int) "adds numbers" 5 (Package.add 2 3)
+
+let () =
+  let open Alcotest in
+  run "Package" [ ("numbers", [ test_case "add" `Quick test_add ]) ]