Several changes

- Add blogpost about nix arrows
- Change header background
- Add RSS link

flake.lock

@@ -2,11 +2,11 @@
   "nodes": {
     "flake-utils": {
       "locked": {
-        "lastModified": 1644229661,
-        "narHash": "sha256-1YdnJAsNy69bpcjuoKdOYQX0YxZBiCYZo4Twxerqv7k=",
+        "lastModified": 1659877975,
+        "narHash": "sha256-zllb8aq3YO3h8B/U0/J1WBgAL8EX5yWf5pMj3G0NAmc=",
         "owner": "numtide",
         "repo": "flake-utils",
-        "rev": "3cecb5b042f7f209c56ffd8371b2711a290ec797",
+        "rev": "c0e246b9b83f637f4681389ecabcb2681b4f3af0",
         "type": "github"
       },
       "original": {
@@ -17,16 +17,16 @@
     },
     "nixpkgs": {
       "locked": {
-        "lastModified": 1646933238,
-        "narHash": "sha256-RZJnLN0o4B35eTnUc2tEAD12X5TNeeJhhvH3Fd6Pmdo=",
+        "lastModified": 1665613119,
+        "narHash": "sha256-VTutbv5YKeBGWou6ladtgfx11h6et+Wlkdyh4jPJ3p0=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "bacbfd713b4781a4a82c1f390f8fe21ae3b8b95b",
+        "rev": "e06bd4b64bbfda91d74f13cb5eca89485d47528f",
         "type": "github"
       },
       "original": {
         "id": "nixpkgs",
-        "ref": "nixos-21.11",
+        "ref": "nixos-22.05",
         "type": "indirect"
       }
     },

flake.nix

@@ -4,12 +4,8 @@
   nixConfig.bash-prompt = "[nix]λ ";
 
   inputs = {
-    nixpkgs.url = "nixpkgs/nixos-21.11";
-
-    flake-utils = {
-      url = "github:numtide/flake-utils";
-      inputs.nixpkgs.follows = "nixpkgs";
-    };
+    nixpkgs.url = "nixpkgs/nixos-22.05";
+    flake-utils.url = "github:numtide/flake-utils";
   };
 
   outputs = { flake-utils, nixpkgs, self }:

src/css/styles.css

@@ -65,6 +65,9 @@ The content `<div>` is where all your content goes.
      padding: 2.5em 2em 0;
      border-bottom: 1px solid #00000088;
      margin-bottom: 2.5em;
+     background-image: url(./images/background.jpg);
+     background-size: cover;
+     height: 25vh;
  }
     /* .header h1 {
         margin: 0.2em 0;
@@ -390,4 +393,4 @@ Hides the menu at `48em`, but modify this based on your app's needs.
   left: 0;
   width: 100%;
   height: 100%;
-}
+}

src/index.html

@@ -7,13 +7,15 @@ title: "Nani"
 ---
 
 <header class="header">
-  <h1 class="display-1">Welcome to nani.wtf</h1>
-  <img
-    alt="A woman sitting on a bench amongst trees at the end of a boardwalk leading to a pond with mountains in the background"
-    src="./images/robert-pearce-UwHN0jU_YqQ-unsplash-800w.jpg"
-    style="max-width:500px;"
-    class="mb-4"
-  />
+  <div class="container">
+    <div class="row">
+      <div class="col-xs-12 col-sm-6 col-md-8 col-centered">
+        <h1 class="display-1 text-white">
+          Welcome to nani.wtf
+        </h1>
+      </div>
+    </div>
+  </div>
 </header>
 <main>
   <section class="content">
@@ -30,7 +32,9 @@ title: "Nani"
                 <div class="card-body">
                   <h5 class="card-title">$title$</h5>
                   <small class="card-text ">$date$</small>
-                  <p class="card-text">$desc$</p>
+                  $if(desc)$
+                    <p class="card-text">$desc$</p>
+                  $endif$
                 </div>
                 <a href="$url$" class="stretched-link"></a>
               </div>

src/posts/2022-10-16-the-arrow-operator.md

@@ -0,0 +1,56 @@
+---
+title: "The nix arrow operator"
+keywords: nix, language, programming-language
+image: './images/nix_banner.png'
+series: "Nix shorts"
+---
+
+There is a specal operator in nix, written as `->`. It is not a c dereference struct pointer operator, nor is it a haskell function type definition. It is a boolean operator, which represents the "implies arrow" from [propositional logic][prop-log]. This is especially useful in nix, because of its usage in modules.
+
+## The `myService` module
+
+Let's say you have made a module for `myService` with two options called `myService.enable`, and `myService.address`. `myService` needs an address in order to work properly. If `myService` is not enabled, the value of `myService.address` doesn't really matter. Set or `null`, the result will be the same either way. If `myService` is enabled however, it is crucial that we report an error if `myService.address` is not set. `myService` can not work without it.
+
+In order to make sure that this never happens, we need to assert that this is not the case. This could be done by asserting that this boolean expression is true.
+
+`((!myService.enable) || myService.address != null)`
+
+or in plain english: "Either myService is not enabled, or the address has to not be null"
+
+This is equivalent to this boolean expression:
+
+`myService.enable -> myService.address != null`
+
+or in plain english: "myService being enabled implies that the address is not null".
+
+Asserting these kinds of inter-setting dependencies are common enough in nix modules to provide grounds for having `->` as its own boolean operator.
+
+## Full example
+
+```nix
+# modules/myService.nix
+{ lib, config }: let
+  cfg = config.myService;
+in {
+  options = {
+    enable = lib.mkEnableOption "myService";
+    address = lib.mkOption {
+      example = "127.0.0.1";
+      description = "The address of myService";
+      type = lib.types.string;
+    };
+  };
+  config = {
+    # ...
+
+    assertions = [
+      {
+        assertion = cfg.enable -> cfg.address != null;
+        message = "myService needs an address";
+      }
+    ];
+  };
+}
+```
+
+[prop-log]: https://iep.utm.edu/prop-log/

src/templates/default.html

@@ -74,6 +74,7 @@
                   <li class="pure-menu-item"><a href="#contact" class="pure-menu-link">Contact</a></li>
                   <li class="pure-menu-item menu-item-divided"><a href="https://git.nani.wtf" class="pure-menu-link">Git</a></li>
                   <li class="pure-menu-item"><a href="https://git.nani.wtf/h7x4/nani.wtf" class="pure-menu-link">Site source</a></li>
+                  <li class="pure-menu-item"><a href="public/rss.xml" class="pure-menu-link">RSS</a></li>
 
               </ul>
           </div>