Prefer Nix flake style

.envrc

@@ -1,2 +1,3 @@
-use_nix
+#!/bin/bash
 
+use flake

.github/workflows/ci-home.yml

@@ -34,8 +34,6 @@ jobs:
     steps:
       - uses: DeterminateSystems/nix-installer-action@v4
       - uses: DeterminateSystems/magic-nix-cache-action@v2
-      - name: Print nixpkgs version
-        run: nix-instantiate --eval -E '(import <nixpkgs> {}).lib.version'
       - name: Register Nix Channels
         run: |
           nix-channel --add https://releases.nixos.org/nixpkgs/nixpkgs-23.11pre509044.3acb5c4264c4/nixexprs.tar.xz nixpkgs

.github/workflows/ci-nix.yml

@@ -5,11 +5,13 @@ on:
     paths:
       - '.github/workflows/ci-nix.yml'
       - '*.nix'
+      - 'flake.*'
       - 'Makefile.toml'
   pull_request:
     paths:
       - '.github/workflows/ci-nix.yml'
       - '*.nix'
+      - 'flake.*'
       - 'Makefile.toml'
   schedule:
     # Every 10:42 JST
@@ -25,5 +27,5 @@ jobs:
       - uses: actions/checkout@v3
       - uses: DeterminateSystems/nix-installer-action@v4
       - uses: DeterminateSystems/magic-nix-cache-action@v2
-      - run: nix-shell --run 'echo This step should be done before any other "nix-shell" steps because of measuring Nix build time'
-      - run: nix-shell --run 'makers ci-dev'
+      - run: nix develop --command echo 'This step should be done before any other "nix develop" steps because of measuring Nix build time'
+      - run: nix develop --command makers ci-dev

CONTRIBUTING.md

@@ -1,7 +1,7 @@
 # Development
 
 1. Install [Nix](https://nixos.org/) package manager
-1. `nix-shell --command 'makers setup'`
+1. `nix develop --command makers setup`
    - `direnv allow` may not work if you have not completed all the installation steps
 
 ## Note

README.md

@@ -12,7 +12,7 @@ Also known as [盆栽(bonsai)](https://en.wikipedia.org/wiki/Bonsai) 🌳
 
 1. Install [Nix](https://nixos.org/) package manager
 1. Install [home-manager](https://github.com/nix-community/home-manager)
-1. `nix-shell --command 'makers apply'`
+1. `nix develop --command makers apply`
 
 ## I don't know ??? - I have just installed OS, I am 🚼
 

flake.nix

@@ -0,0 +1,43 @@
+{
+  inputs = {
+    # Candidate channels
+    #   - https://github.com/kachick/anylang-template/issues/17
+    #   - https://discourse.nixos.org/t/differences-between-nix-channels/13998
+    # How to update the revision
+    #   - `nix flake update --commit-lock-file` # https://nixos.org/manual/nix/stable/command-ref/new-cli/nix3-flake-update.html
+    # TODO: Refer a popular channel in another issues
+    # nixpkgs.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
+    nixpkgs.url = "https://releases.nixos.org/nixpkgs/nixpkgs-23.11pre509044.3acb5c4264c4/nixexprs.tar.xz";
+    flake-utils.url = "github:numtide/flake-utils";
+  };
+
+  outputs = { self, nixpkgs, flake-utils }:
+    flake-utils.lib.eachDefaultSystem (system:
+      let
+        pkgs = nixpkgs.legacyPackages.${system};
+      in
+      {
+        devShells.default = with pkgs;
+          mkShell {
+            buildInputs = [
+              # https://github.com/NixOS/nix/issues/730#issuecomment-162323824
+              bashInteractive
+
+              dprint
+              shellcheck
+              shfmt
+              nil
+              nixpkgs-fmt
+              gitleaks
+              cargo-make
+              typos
+              go_1_20
+
+              # To get sha256 around pkgs.fetchFromGitHub in CLI
+              nix-prefetch-git
+              jq
+            ];
+          };
+      }
+    );
+}