docs: add nixpkgs examples

6 files changed, 104 insertions, 2 deletions

diff --git a/.gitignore b/.gitignore
index 6572f3d..1458f96 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,4 +1,4 @@
 /yae
 .pre-commit-config.yaml
 result
-yae.json
+/yae.json
diff --git a/README.md b/README.md
index 59ea528..c2354ab 100644
--- a/README.md
+++ b/README.md
@@ -109,12 +109,28 @@ exported `inputs.yae.packages.${pkgs.system}.yae` package.
 To add Yae support to your Nix expression after running `yae init`, just read
 from the Yae environment file. See the example below for more details.
 
-### Nix Example
+### Examples
+
+Check out [`examples/nixpkgs`](./examples/nixpkgs) for a pure Nix example of Yae
+in action. This example is a little large since it constrains itself to **zero**
+inputs and manually constructs multi-system support. In a real-world scenario,
+you'd actually use something like [flake-utils](https://github.com/numtide/flake-utils)
+to replace all of the boilerplate. For this reason, [`examples/nixpkgs-simple`](./examples/nixpkgs-simple)
+exists, which functions identically, but uses `builtins.currentSystem` to
+populate the `nixpkgs.system` attribute. (requires `--impure`)
+
+If Nixpkgs ever goes out of date in these theorectical examples, just run
+`yae update`!
+
+#### Real-world Example
 
 Here's an example snippet taken from Tsutsumi's [`zen-browser-bin` package](https://github.com/Fuwn/tsutsumi/blob/main/pkgs/zen-browser-bin.nix)
 and [`yae.json`](https://github.com/Fuwn/tsutsumi/blob/main/yae.json#L59-L67)
 showcasing Yae in action.
 
+<details closed>
+  <summary>Expand this!</summary>
+
 ```nix
 # pkgs/zen-browser-bin.nix
 
@@ -146,6 +162,7 @@ import "${self}/lib/zen-browser-bin.nix" {
   # inherit (yae.zen-browser-twilight-bin) sha256 version;
 } { inherit pkgs; }
 ```
+</details>
 
 ## `--help`
 
diff --git a/examples/nixpkgs-simple/flake.nix b/examples/nixpkgs-simple/flake.nix
new file mode 100644
index 0000000..2903230
--- /dev/null
+++ b/examples/nixpkgs-simple/flake.nix
@@ -0,0 +1,18 @@
+{
+  outputs =
+    { self }:
+    let
+      nixpkgs = (builtins.fromJSON (builtins.readFile "${self}/yae.json")).nixpkgs;
+
+      pkgs =
+        import
+          (builtins.fetchTarball {
+            inherit (nixpkgs) url sha256;
+          })
+          {
+          };
+    in
+    {
+      packages.${pkgs.system}.hello = pkgs.hello;
+    };
+}
diff --git a/examples/nixpkgs-simple/yae.json b/examples/nixpkgs-simple/yae.json
new file mode 100644
index 0000000..54b371c
--- /dev/null
+++ b/examples/nixpkgs-simple/yae.json
@@ -0,0 +1,10 @@
+{
+  "nixpkgs": {
+    "url": "https://github.com/NixOS/nixpkgs/archive/nixos-unstable.tar.gz",
+    "sha256": "1wn29537l343lb0id0byk0699fj0k07m1n2d7jx2n0ssax55vhwy",
+    "unpack": true,
+    "type": "git",
+    "version": "nixos-unstable",
+    "url_template": "https://github.com/NixOS/nixpkgs/archive/{version}.tar.gz"
+  }
+}
diff --git a/examples/nixpkgs/flake.nix b/examples/nixpkgs/flake.nix
new file mode 100644
index 0000000..7dd28a4
--- /dev/null
+++ b/examples/nixpkgs/flake.nix
@@ -0,0 +1,47 @@
+{
+  outputs =
+    { self }:
+    let
+      nixpkgs = (builtins.fromJSON (builtins.readFile "${self}/yae.json")).nixpkgs;
+
+      systemsFlakeExposed = [
+        "x86_64-linux"
+        "aarch64-linux"
+        "x86_64-darwin"
+        "armv6l-linux"
+        "armv7l-linux"
+        "i686-linux"
+        "aarch64-darwin"
+        "powerpc64le-linux"
+        "riscv64-linux"
+        "x86_64-freebsd"
+      ];
+
+      forEachSystem =
+        systems: action:
+        builtins.listToAttrs (
+          map (system: {
+            name = system;
+            value = action system;
+          }) systems
+        );
+    in
+    {
+      packages = (forEachSystem systemsFlakeExposed) (
+        system:
+        let
+          pkgs =
+            import
+              (builtins.fetchTarball {
+                inherit (nixpkgs) url sha256;
+              })
+              {
+                inherit system;
+              };
+        in
+        {
+          hello = pkgs.hello;
+        }
+      );
+    };
+}
diff --git a/examples/nixpkgs/yae.json b/examples/nixpkgs/yae.json
new file mode 100644
index 0000000..54b371c
--- /dev/null
+++ b/examples/nixpkgs/yae.json
@@ -0,0 +1,10 @@
+{
+  "nixpkgs": {
+    "url": "https://github.com/NixOS/nixpkgs/archive/nixos-unstable.tar.gz",
+    "sha256": "1wn29537l343lb0id0byk0699fj0k07m1n2d7jx2n0ssax55vhwy",
+    "unpack": true,
+    "type": "git",
+    "version": "nixos-unstable",
+    "url_template": "https://github.com/NixOS/nixpkgs/archive/{version}.tar.gz"
+  }
+}