NixOS: add part about Nix

spotlight_courses/HS24_NixOS/main.typ

@@ -44,8 +44,8 @@
 == Today's topics
 - What sets *`NixOS`* apart from other distros? 
 
-- benefits of *`nix`* and *`NixOS`*
-- Understand *why* nix is cool and why it might be for you
+- benefits of *`Nix`* and *`NixOS`*
+- Understand *why* Nix is cool and why it might be for you
 - configuring *`NixOS`*
 - *toolbox* of commands / websites
 - some *interesting projects* for NixOS
@@ -77,7 +77,43 @@
   - Distribute your builds accross an unlimited number of machines, without any hassle
 
 = A Nix crash course
+== The Nix language basics
+#columns(2, [
+- A piece of nix code is a _Nix expression_
+- Evaluating that expression gives a _value_
+- The content of a _Nix file_ is a _Nix expression_
+```nix
+> 1 + 1
+2
+
+> "This is Nix!"
+"This is Nix!"
+```
+#colbreak()
+*Names and values:*
+- Assign names to values
+```nix
+> a = 1
+
+> a
+a
 
+> b = true
+
+> b
+true
+```
+])
+
+=== Attribute sets:
+- collection of name-value pairs
+```nix
+> {a = 1; b = "2"; c = 3.0;}
+{
+  a = 1;
+  b = "2";
+  c = 3;
+}```
 == A simple bash script
 #columns(2, [
 
@@ -330,6 +366,38 @@ in
     };
   }
 ```
+=== Put it into a system's packages!
+#text(size:10pt, [
+#columns(2, [
+```nix
+let
+  nixpkgs = fetchTarball "https://github.com/NixOS/nixpkgs/archive/nixos-24.05.tar.gz";
+  pkgs = import nixpkgs {};
+  what-is-my-ip = import ./what-is-my-ip.nix {inherit pkgs;};
+  nixos = import "${nixpkgs}/nixos" {
+    configuration = {
+      users.users.alice = {
+        isNormalUser = true;
+        # enable sudo
+        extraGroups = ["wheel"];
+        packages = [
+          what-is-my-ip
+        ];
+        initialPassword = "tux";
+      };
+
+      system.stateVersion = "24.05";
+    };
+  };
+in
+  nixos.vm
+```
+#text(size: 15pt,[
+- Build the vm
+  - (using nix-build what-is-my-ip-vm.nix)
+- have what-is-my-ip installed!
+])])
+])
 // https://fzakaria.com/2024/07/05/learn-nix-the-fun-way.html
 
 = NixOS
@@ -756,12 +824,59 @@ config.vim = {
 #link("https://github.com/NotAShelf/nvf")
   ])
 ])
+
+== Docker!
+
+#columns(2,
+[
+#text(
+size: 13pt, 
+[```nix
+{ pkgs ? import <nixpkgs> {system = "x86_64-linux;" }}: let 
+what-is-my-ip = import ./what-is-my-ip.nix {inherit pkgs;};
+in
+pkgs.dockerTools.buildImage {
+  name = "what-is-my-ip-docker";
+  config = {
+    Cmd = [ "${what-is-my-ip}/bin/what-is-my-ip" ];
+  };
+}
+```])])
+- Works, but is it really better than using docker normally?
+=== Easy layered Docker iamges
+
+#columns(2,
+[
+#text(
+size: 13pt, 
+[```nix
+{ pkgs ? import <nixpkgs> {system = "x86_64-linux;" }}: let 
+what-is-my-ip = import ./what-is-my-ip.nix {inherit pkgs;};
+in
+pkgs.dockerTools.buildLayeredImage {
+  name = "what-is-my-ip-docker";
+  config = {
+    Cmd = [ "${what-is-my-ip}/bin/what-is-my-ip" ];
+  };
+}
+```])
+#colbreak()
+- puts each dependency into a seperate layer
+- updating a single package/dependency?
+  - only update that layer, and upload the part of the image which actually changed
+- easy version controlling with git
+])
+
 = Toolbox
 
 == CLI
 === `nix repl`
 - search for packages
-
+#figure(
+  caption: "extra nix features in my config"
+)[
+  #image("img/nix-repl-pkgs.png", width: 70%)
+]
 
 === `nix repl` 
 - inspect configuration
@@ -783,13 +898,6 @@ config.vim = {
 
 = packaging
 
-== pitfalls
-
-- Let me just copy the hash of another package until it fetches
-  $==>$ nothing happens, no error???
-
-  - why? identity of derivation: hash
-
 = stylix
 
 == Styling