Post + hero updates

pull/1/head
mat ess 2022-10-10 19:12:16 -04:00
parent 9165d51f49
commit 8434aa24ff
3 changed files with 15 additions and 15 deletions

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@ -6,13 +6,9 @@ description = "a short announcement post for a few interactive cellular automata
tags = ["cellular-automata", "lua", "löve2d"] tags = ["cellular-automata", "lua", "löve2d"]
[extra] [extra]
hero = true hero = true
heroPrompt = "The oracle reading the future from Conway's Game of Life, technomancer aesthetic, digital illustration, 8k uhd"
+++ +++
<figure>
<img class="hero" alt="The oracle reading the future from Conway's Game of Life, technomancer aesthetic, digital illustration, 8k uhd - generated using Stable Diffusion" src=hero.png />
<figcaption><h4><i>The oracle reading the future from Conway's Game of Life, technomancer aesthetic, digital illustration, 8k uhd</i> - generated using Stable Diffusion</h4></figcaption>
</figure>
after reading [Andrew Healey's blog post about Langton's Ant](https://healeycodes.com/virtual-ants), i found myself inspired to reimplement some of his work. i've read numerous rave reviews of löve2d for writing simple toys, so i decided to give that a shot here as well. Langton's Ant went well enough that i also implemented Life and Wireworld. after reading [Andrew Healey's blog post about Langton's Ant](https://healeycodes.com/virtual-ants), i found myself inspired to reimplement some of his work. i've read numerous rave reviews of löve2d for writing simple toys, so i decided to give that a shot here as well. Langton's Ant went well enough that i also implemented Life and Wireworld.
[check the toys out here; there are instructions for running with löve2d directly or using nix](https://git.mat.services/mat/love-cellular-automata). the code is hosted on a personal instance of gitea, so if you want to collaborate or share feedback, you'll have to request an account or shoot me an email. [check the toys out here; there are instructions for running with löve2d directly or using nix](https://git.mat.services/mat/love-cellular-automata). the code is hosted on a personal instance of gitea, so if you want to collaborate or share feedback, you'll have to request an account or shoot me an email.

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@ -1,19 +1,14 @@
+++ +++
title = "passing command line arguments to nix flakes" title = "passing command line arguments to nix flakes"
date = "2022-10-09" date = "2022-10-10"
description = "a tutorial on 'breaking' the hermeticity of nix flakes by adding convenient command line flags" description = "a tutorial on 'breaking' the hermeticity of nix flakes by adding convenient command line flags"
draft = true
[taxonomies] [taxonomies]
tags = ["nix"] tags = ["nix"]
[extra] [extra]
hero = true hero = true
heroPrompt = "A rogue program hacking through the firewall, in the style of Tron Legacy, cyberpunk vibe, digital render, 8k uhd, unreal engine</i> - generated using Stable Diffusion"
+++ +++
<figure>
<img class="hero" alt="A rogue program hacking through the firewall, in the style of Tron Legacy, cyberpunk vibe, digital render, 8k uhd, unreal engine - generated using Stable Diffusion" src=hero.png />
<figcaption><h4><i>A rogue program hacking through the firewall, in the style of Tron Legacy, cyberpunk vibe, digital render, 8k uhd, unreal engine</i> - generated using Stable Diffusion</h4></figcaption>
</figure>
[Nix flakes](https://serokell.io/blog/practical-nix-flakes) are very useful, but the feature of a [fully hermetic build](https://bazel.build/basics/hermeticity) also means that they carry with them a certain degree of inflexibility. [Users have asked for a mechanism to parameterize flakes](https://github.com/NixOS/nix/issues/2861#issuecomment-891521971), but there seems to be no interest from the Nix maintainers in adding such a feature. [Nix flakes](https://serokell.io/blog/practical-nix-flakes) are very useful, but the feature of a [fully hermetic build](https://bazel.build/basics/hermeticity) also means that they carry with them a certain degree of inflexibility. [Users have asked for a mechanism to parameterize flakes](https://github.com/NixOS/nix/issues/2861#issuecomment-891521971), but there seems to be no interest from the Nix maintainers in adding such a feature.
> While many readers will be very familiar with the concept of a function and the idea of parameterizing some piece of code or data, others might appreciate a bit of background. [Take a look at the appendix for a tangential explainer of some fundamental ideas referenced throughout this post.](#appendix) > While many readers will be very familiar with the concept of a function and the idea of parameterizing some piece of code or data, others might appreciate a bit of background. [Take a look at the appendix for a tangential explainer of some fundamental ideas referenced throughout this post.](#appendix)
@ -22,7 +17,7 @@ hero = true
From outside of a flake's Nix expression, the flake is a black box, a mapping from its input sources to the artifacts that it outputs. There is no built-in way to pass an arbitrary value, a boolean flag or string, from the command line in order to override a deeply nested configuration embedded in your flake. In most cases, this is fine, and you can work around many apparent needs for a one off override by building separate outputs for different purposes. Your flakes will probably come out better designed if you can use them strictly as intended. From outside of a flake's Nix expression, the flake is a black box, a mapping from its input sources to the artifacts that it outputs. There is no built-in way to pass an arbitrary value, a boolean flag or string, from the command line in order to override a deeply nested configuration embedded in your flake. In most cases, this is fine, and you can work around many apparent needs for a one off override by building separate outputs for different purposes. Your flakes will probably come out better designed if you can use them strictly as intended.
A real-life use case where a command line override would come in handy comes from my own [nix-darwin](https://daiderd.com/nix-darwin/) configuration, where I have my [homebrew](https://brew.sh/) formulas and casks specified. I like to let Nix manage installing and upgrading these packages, but unfortunately the process to check for updates eats up a bit of time. When I'm testing a new change to some other part of my nix-darwin setup, I don't like to waste time repeatedly checking for homebrew updates. I could manually disable homebrew updates, but then I have to remember to flip it back on. Wouldn't it be nice to have two commands? Something like: A real-life use case where a command line override would come in handy comes from my own [nix-darwin](https://daiderd.com/nix-darwin/) configuration, where I have my [homebrew](https://brew.sh/) formulas and casks specified. I like to let Nix manage installing and upgrading these packages, but unfortunately the process to check for updates eats up a bit of time. When I'm testing a new change to some other part of my nix-darwin setup, I don't like to waste time repeatedly checking for homebrew updates. I could manually disable homebrew updates, but then I'd have to remember to flip it back on. Wouldn't it be nice to have two commands? Something like:
```bash ```bash
# rebuild the full system flake, when we want to perform homebrew updates # rebuild the full system flake, when we want to perform homebrew updates
darwin-rebuild switch --flake <flake-path> darwin-rebuild switch --flake <flake-path>
@ -61,7 +56,7 @@ nix eval --override-input my-flag github:boolean-option/false --raw '.#message'
So far, every flake-oriented Nix command I have tried supports the `override-input` flag, so this is a pretty reliable mechanism for passing in overrides where needed. So far, every flake-oriented Nix command I have tried supports the `override-input` flag, so this is a pretty reliable mechanism for passing in overrides where needed.
[Take a look](https://git.mat.services/mat/dotfiles.nix/src/branch/main/flake.nix#L16-L17) [at how I use this](https://git.mat.services/mat/dotfiles.nix/src/branch/main/flake.nix#L16-L17) [in my own system flake](https://git.mat.services/mat/dotfiles.nix/src/branch/main/darwin/homebrew.nix#L31). [Take a look](https://git.mat.services/mat/dotfiles.nix/src/branch/main/flake.nix#L16-L17) [at how I use this](https://git.mat.services/mat/dotfiles.nix/src/branch/main/flake.nix#L256) [in my own system flake](https://git.mat.services/mat/dotfiles.nix/src/branch/main/darwin/homebrew.nix#L31).
## Appendix ## Appendix
[Go back to the article](#jumpback) [Go back to the article](#jumpback)

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@ -75,6 +75,15 @@
{% endif %} {% endif %}
</div> </div>
{% if page.extra.hero %}
<figure>
<img class="hero" alt="{{ page.extra.heroPrompt }} - generated using Stable Diffusion" src=hero.png />
<figcaption>
<h4><i>{{ page.extra.heroPrompt }}</i> - generated using Stable Diffusion</h4>
</figcaption>
</figure>
{% endif %}
{% if page.extra.tldr %} {% if page.extra.tldr %}
<div class="tldr"> <div class="tldr">
<strong>tl;dr:</strong> <strong>tl;dr:</strong>
@ -83,7 +92,7 @@
{% endif %} {% endif %}
{# Optional table of contents #} {# Optional table of contents #}
{% if config.extra.toc | default(value=false) %} {% if page.extra.toc | default(value=false) %}
{% if page.toc %} {% if page.toc %}
<h2>Table of Contents</h2> <h2>Table of Contents</h2>
<ul> <ul>