diff --git a/flake.lock b/flake.lock index c8f9a03..82917b9 100644 --- a/flake.lock +++ b/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" } }, diff --git a/flake.nix b/flake.nix index b2cb153..a43c72f 100644 --- a/flake.nix +++ b/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 }: diff --git a/src/css/styles.css b/src/css/styles.css index 47c377a..5f1c57f 100644 --- a/src/css/styles.css +++ b/src/css/styles.css @@ -65,6 +65,9 @@ The content `
` 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%; -} \ No newline at end of file +} diff --git a/src/images/background.jpg b/src/images/background.jpg new file mode 100644 index 0000000..cf777a6 Binary files /dev/null and b/src/images/background.jpg differ diff --git a/src/images/nix_banner.png b/src/images/nix_banner.png new file mode 100644 index 0000000..b1b1df6 Binary files /dev/null and b/src/images/nix_banner.png differ diff --git a/src/index.html b/src/index.html index e5573c2..a0f3a25 100644 --- a/src/index.html +++ b/src/index.html @@ -7,13 +7,15 @@ title: "Nani" ---
-

Welcome to nani.wtf

- A woman sitting on a bench amongst trees at the end of a boardwalk leading to a pond with mountains in the background +
+
+
+

+ Welcome to nani.wtf +

+
+
+
@@ -30,7 +32,9 @@ title: "Nani"
$title$
$date$ -

$desc$

+ $if(desc)$ +

$desc$

+ $endif$
diff --git a/src/posts/2022-10-16-the-arrow-operator.md b/src/posts/2022-10-16-the-arrow-operator.md new file mode 100644 index 0000000..24f8297 --- /dev/null +++ b/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/ diff --git a/src/templates/default.html b/src/templates/default.html index b5e62f3..11557ed 100644 --- a/src/templates/default.html +++ b/src/templates/default.html @@ -74,6 +74,7 @@
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