---
title: "bluesky"
url: "https://github.com/mas-4/bluesky"
featureImage: ""
short: "bluesky"
category: "tooling"
ai: ""
order: "03"
year: "2022"
tags: ["c++", "c", "static site generator", "md4c"]
---
bluesky is the static site generator I wrote in 2022 to build this site. When
my dog Sky died that May, I sat down to write about her and Gatsby's
development server refused to start. So I wrote my own generator, modeled on
the wonderfully simple [Sergey](https://sergey.cool/), and named it after her.
It does three things: includes, templates with named slots, and directories of
markdown turned into pages with a list of links to them. I started it in C
([bluesky-c](https://github.com/mas-4/bluesky-c)), struggled for two weeks,
switched to C++, and finished it that September. It built this site until
October 2026.
In 2024, while reading *Crafting Interpreters*, I rewrote it in C as
[nowclaire](https://github.com/mas-4/nowclaire), to try out the scanning and
lexing I was learning. Its successor, [skyblue](/projects/cprime), was
rewritten in c′ by Claude.
<sky-template path="main.html" />
<sky-block name="title">${frontmatter.title} · </sky-block>
<sky-block name="content">
<article class="project">
<a class="back" href="/projects">← all projects</a>
<p class="pills"><span class="pill">${frontmatter.category}</span><span class="pill pill-ai">${frontmatter.ai}</span><span class="year">${frontmatter.year}</span></p>
<h1>${frontmatter.title}</h1>
<a class="visit" href="${frontmatter.url}">${frontmatter.url}</a>
<img class="feature" src="${frontmatter.featureImage}" alt="" />
<div class="markdown">
<sky-slot name="content" />
</div>
</article>
</sky-block>
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8" />
<script><sky-include path="theme.js" /></script>
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<title><sky-slot name="title" />${meta.title}</title>
<meta name="description" content="${meta.description}" />
<meta name="theme-color" content="#142420" />
<link rel="icon" href="/favicon.svg" type="image/svg+xml" />
<link rel="stylesheet" href="/style.css" />
</head>
<body>
<!-- Every page is a sheet of paper lying on the source it was built
from. This checkbox lifts the sheet; no JavaScript involved. -->
<input type="checkbox" id="xray" class="xray" aria-label="Show the source of this page" />
<div class="desk">
<div class="sheet">
<!-- Under the paper, the page's source, for the candle to show. -->
<div class="underside" aria-hidden="true"><sky-sources item="underside.html" /></div>
<div class="paper" aria-hidden="true"></div>
<svg class="flame" viewBox="0 0 24 44" aria-hidden="true">
<defs>
<radialGradient id="flame-body" cx="50%" cy="78%" r="62%">
<stop offset="0" stop-color="#fffbe8" />
<stop offset="0.35" stop-color="#ffe08a" />
<stop offset="0.7" stop-color="#ff9a2e" />
<stop offset="1" stop-color="#e2470f" stop-opacity="0" />
</radialGradient>
<radialGradient id="flame-core" cx="50%" cy="80%" r="55%">
<stop offset="0" stop-color="#ffffff" />
<stop offset="0.6" stop-color="#fff3c4" />
<stop offset="1" stop-color="#ffd166" stop-opacity="0" />
</radialGradient>
</defs>
<path class="flame-body" fill="url(#flame-body)" d="M12 1C15 11 22 18 21 29 20 37 16 43 12 43 8 43 4 37 3 29 2 18 9 11 12 1Z" />
<path class="flame-core" fill="url(#flame-core)" d="M12 15C14 21 17 26 16.5 32 16 37 14 40 12 40 10 40 8 37 7.5 32 7 26 10 21 12 15Z" />
<ellipse class="flame-base" cx="12" cy="40" rx="3.2" ry="2" fill="#5aa9ff" opacity="0.45" />
</svg>
<label for="xray" class="curl" title="Lift the page to see what it's made of" aria-hidden="true"></label>
<label for="xray" class="sheet-cover" title="Back to the page"></label>
<sky-include path="_nav.html" />
<main class="page">
<sky-slot name="content" />
</main>
<sky-include path="_footer.html" />
</div>
<aside class="ground" aria-label="The source of this page">
<header class="ground-head">
<p>
<a href="https://github.com/mas-4/skyblue">skyblue</a> built this
page from these files, in the order it used them.
</p>
<label for="xray" class="ground-close">back to the page →</label>
</header>
<sky-sources item="source.html" />
</aside>
</div>
<script><sky-include path="candle.js" /></script>
</body>
</html>
// The light switch. Until it's flipped, the page follows the system's
// light or dark preference (that part is CSS). Flipping it picks the other
// one and remembers it. This runs in <head>, so a saved choice applies
// before the page is drawn.
(() => {
const root = document.documentElement;
const system = matchMedia("(prefers-color-scheme: dark)");
try {
const saved = localStorage.getItem("theme");
if (saved === "light" || saved === "dark") root.dataset.theme = saved;
} catch {}
const isDark = () => (root.dataset.theme ? root.dataset.theme === "dark" : system.matches);
document.addEventListener("DOMContentLoaded", () => {
const button = document.querySelector(".theme-toggle");
if (!button) return;
const show = () => button.setAttribute("aria-checked", String(isDark()));
button.hidden = false;
show();
system.addEventListener("change", show);
button.addEventListener("click", () => {
root.dataset.theme = isDark() ? "light" : "dark";
try {
localStorage.setItem("theme", root.dataset.theme);
} catch {}
show();
});
});
})();
<header class="site-header">
<nav class="nav">
<a class="brand" href="/">
<svg class="brand-mark" viewBox="0 0 32 32" aria-hidden="true">
<path d="M2 13c4 0 4-3 7-3s3 3 7 3 4-3 7-3 3 3 7 3" />
<path d="M2 20c4 0 4-3 7-3s3 3 7 3 4-3 7-3 3 3 7 3" />
</svg>
${meta.title}
</a>
<div class="nav-links">
<a href="/">home</a>
<a href="/about">about</a>
<a href="/projects">projects</a>
<a href="/orbits">orbits</a>
<label for="xray" class="source-toggle" title="Lift the page to see what it's made of">source</label>
</div>
<button type="button" class="theme-toggle" role="switch" aria-checked="false" aria-label="Dark mode" title="Light or dark" hidden><span class="knob"></span></button>
</nav>
</header>
<footer class="site-footer">
<div class="social">
<a href="https://github.com/mas-4">
<svg
aria-labelledby="svg-inline--fa-title-Yppzrr98YU17"
role="img"
xmlns="http://www.w3.org/2000/svg"
viewBox="0 0 496 512"
>
<title id="svg-inline--fa-title-Yppzrr98YU17">GitHub</title>
<path
fill="currentColor"
d="M165.9 397.4c0 2-2.3 3.6-5.2 3.6-3.3.3-5.6-1.3-5.6-3.6 0-2 2.3-3.6 5.2-3.6 3-.3 5.6 1.3 5.6 3.6zm-31.1-4.5c-.7 2 1.3 4.3 4.3 4.9 2.6 1 5.6 0 6.2-2s-1.3-4.3-4.3-5.2c-2.6-.7-5.5.3-6.2 2.3zm44.2-1.7c-2.9.7-4.9 2.6-4.6 4.9.3 2 2.9 3.3 5.9 2.6 2.9-.7 4.9-2.6 4.6-4.6-.3-1.9-3-3.2-5.9-2.9zM244.8 8C106.1 8 0 113.3 0 252c0 110.9 69.8 205.8 169.5 239.2 12.8 2.3 17.3-5.6 17.3-12.1 0-6.2-.3-40.4-.3-61.4 0 0-70 15-84.7-29.8 0 0-11.4-29.1-27.8-36.6 0 0-22.9-15.7 1.6-15.4 0 0 24.9 2 38.6 25.8 21.9 38.6 58.6 27.5 72.9 20.9 2.3-16 8.8-27.1 16-33.7-55.9-6.2-112.3-14.3-112.3-110.5 0-27.5 7.6-41.3 23.6-58.9-2.6-6.5-11.1-33.3 2.6-67.9 20.9-6.5 69 27 69 27 20-5.6 41.5-8.5 62.8-8.5s42.8 2.9 62.8 8.5c0 0 48.1-33.6 69-27 13.7 34.7 5.2 61.4 2.6 67.9 16 17.7 25.8 31.5 25.8 58.9 0 96.5-58.9 104.2-114.8 110.5 9.2 7.9 17 22.9 17 46.4 0 33.7-.3 75.4-.3 83.6 0 6.5 4.6 14.4 17.3 12.1C428.2 457.8 496 362.9 496 252 496 113.3 383.5 8 244.8 8zM97.2 352.9c-1.3 1-1 3.3.7 5.2 1.6 1.6 3.9 2.3 5.2 1 1.3-1 1-3.3-.7-5.2-1.6-1.6-3.9-2.3-5.2-1zm-10.8-8.1c-.7 1.3.3 2.9 2.3 3.9 1.6 1 3.6.7 4.3-.7.7-1.3-.3-2.9-2.3-3.9-2-.6-3.6-.3-4.3.7zm32.4 35.6c-1.6 1.3-1 4.3 1.3 6.2 2.3 2.3 5.2 2.6 6.5 1 1.3-1.3.7-4.3-1.3-6.2-2.2-2.3-5.2-2.6-6.5-1zm-11.4-14.7c-1.6 1-1.6 3.6 0 5.9 1.6 2.3 4.3 3.3 5.6 2.3 1.6-1.3 1.6-3.9 0-6.2-1.4-2.3-4-3.3-5.6-2z"
></path>
</svg>
</a>
<a href="https://stackoverflow.com/users/9691276/mas">
<svg
aria-labelledby="svg-inline--fa-title-kGxnyVLHc64Z"
role="img"
xmlns="http://www.w3.org/2000/svg"
viewBox="0 0 384 512"
>
<title id="svg-inline--fa-title-kGxnyVLHc64Z">StackOverflow</title>
<path
fill="currentColor"
d="M290.7 311L95 269.7 86.8 309l195.7 41zm51-87L188.2 95.7l-25.5 30.8 153.5 128.3zm-31.2 39.7L129.2 179l-16.7 36.5L293.7 300zM262 32l-32 24 119.3 160.3 32-24zm20.5 328h-200v39.7h200zm39.7 80H42.7V320h-40v160h359.5V320h-40z"
></path>
</svg>
</a>
<a href="https://www.linkedin.com/in/michael-sendker">
<svg
aria-labelledby="svg-inline--fa-title-BaV39z6dqIIX"
role="img"
xmlns="http://www.w3.org/2000/svg"
viewBox="0 0 448 512"
>
<title id="svg-inline--fa-title-BaV39z6dqIIX">LinkedIn</title>
<path
fill="currentColor"
d="M416 32H31.9C14.3 32 0 46.5 0 64.3v383.4C0 465.5 14.3 480 31.9 480H416c17.6 0 32-14.5 32-32.3V64.3c0-17.8-14.4-32.3-32-32.3zM135.4 416H69V202.2h66.5V416zm-33.2-243c-21.3 0-38.5-17.3-38.5-38.5S80.9 96 102.2 96c21.2 0 38.5 17.3 38.5 38.5 0 21.3-17.2 38.5-38.5 38.5zm282.1 243h-66.4V312c0-24.8-.5-56.7-34.5-56.7-34.6 0-39.9 27-39.9 54.9V416h-66.4V202.2h63.7v29.2h.9c8.9-16.8 30.6-34.5 62.9-34.5 67.2 0 79.7 44.3 79.7 101.9V416z"
></path>
</svg>
</a>
<a href="https://raw.githubusercontent.com/mas-4/resume/master/main.pdf">
<svg
aria-labelledby="svg-inline--fa-title-fmQP80A0S9GF"
role="img"
xmlns="http://www.w3.org/2000/svg"
viewBox="0 0 384 512"
>
<title id="svg-inline--fa-title-fmQP80A0S9GF">Résumé</title>
<path
fill="currentColor"
d="M181.9 256.1c-5-16-4.9-46.9-2-46.9 8.4 0 7.6 36.9 2 46.9zm-1.7 47.2c-7.7 20.2-17.3 43.3-28.4 62.7 18.3-7 39-17.2 62.9-21.9-12.7-9.6-24.9-23.4-34.5-40.8zM86.1 428.1c0 .8 13.2-5.4 34.9-40.2-6.7 6.3-29.1 24.5-34.9 40.2zM248 160h136v328c0 13.3-10.7 24-24 24H24c-13.3 0-24-10.7-24-24V24C0 10.7 10.7 0 24 0h200v136c0 13.2 10.8 24 24 24zm-8 171.8c-20-12.2-33.3-29-42.7-53.8 4.5-18.5 11.6-46.6 6.2-64.2-4.7-29.4-42.4-26.5-47.8-6.8-5 18.3-.4 44.1 8.1 77-11.6 27.6-28.7 64.6-40.8 85.8-.1 0-.1.1-.2.1-27.1 13.9-73.6 44.5-54.5 68 5.6 6.9 16 10 21.5 10 17.9 0 35.7-18 61.1-61.8 25.8-8.5 54.1-19.1 79-23.2 21.7 11.8 47.1 19.5 64 19.5 29.2 0 31.2-32 19.7-43.4-13.9-13.6-54.3-9.7-73.6-7.2zM377 105L279 7c-4.5-4.5-10.6-7-17-7h-6v128h128v-6.1c0-6.3-2.5-12.4-7-16.9zm-74.1 255.3c4.1-2.7-2.5-11.9-42.8-9 37.1 15.8 42.8 9 42.8 9z"
></path>
</svg>
</a>
</div>
<!-- skyblue fills these in as it builds the site. -->
<pre class="receipt" aria-label="How this page was built"><span class="prompt">$</span> skyblue --version
skyblue <a href="https://github.com/mas-4/skyblue">${sky.version}</a> (compiled by cprime <a href="https://github.com/mas-4/cprime">${sky.compiler}</a>)
<span class="prompt">$</span> skyblue -i src -o build
skyblue: ${sky.pages} pages and ${sky.files} files -> build
<span class="note"># ${sky.date}, ${sky.time}, ${sky.ms} ms. Two small scripts: the candle and the light switch.</span></pre>
<p class="copyright">© 2022–2026 Michael Sendker</p>
</footer>
// The candle. Hold the pointer over the words and a flame lights above
// them: the paper warms and thins, and the page's source shows through
// from underneath. Only over the letters themselves, not blank paper.
// Without this script the paper simply stays opaque.
(() => {
const sheet = document.querySelector(".sheet");
if (!sheet || !matchMedia("(hover: hover) and (pointer: fine)").matches) return;
// Is (x, y) on a letter? Find the text position under the point, then
// check that the point is inside the box of the character on either side.
const range = document.createRange();
const overGlyph = (x, y) => {
let node, offset;
if (document.caretPositionFromPoint) {
const pos = document.caretPositionFromPoint(x, y);
if (pos) [node, offset] = [pos.offsetNode, pos.offset];
} else if (document.caretRangeFromPoint) {
const r = document.caretRangeFromPoint(x, y);
if (r) [node, offset] = [r.startContainer, r.startOffset];
}
if (!node || node.nodeType !== Node.TEXT_NODE || !sheet.contains(node)) return false;
for (const i of [offset - 1, offset]) {
if (i < 0 || i >= node.length || /\s/.test(node.data[i])) continue;
range.setStart(node, i);
range.setEnd(node, i + 1);
for (const box of range.getClientRects())
if (x >= box.left && x <= box.right && y >= box.top && y <= box.bottom) return true;
}
return false;
};
let x = 0, y = 0, queued = false, dousing = 0;
const draw = () => {
queued = false;
const box = sheet.getBoundingClientRect();
sheet.style.setProperty("--cx", x - box.left + "px");
sheet.style.setProperty("--cy", y - box.top + "px");
if (overGlyph(x, y)) {
clearTimeout(dousing);
dousing = 0;
sheet.classList.add("lit");
} else if (!dousing && sheet.classList.contains("lit")) {
// A moment's grace, so it doesn't strobe across the spaces between words
dousing = setTimeout(() => {
sheet.classList.remove("lit");
dousing = 0;
}, 350);
}
};
sheet.addEventListener("pointermove", (e) => {
[x, y] = [e.clientX, e.clientY];
if (!queued) {
queued = true;
requestAnimationFrame(draw);
}
});
sheet.addEventListener("pointerleave", () => {
clearTimeout(dousing);
dousing = 0;
sheet.classList.remove("lit");
});
})();
<section class="source">
<header class="source-head">
<a href="https://github.com/mas-4/standingwater-flat/blob/main/src/${source.path}">${source.path}</a>
<span>${source.lines} lines</span>
</header>
<pre class="listing"><code>${source.code}</code></pre>
</section>
<pre class="listing"><code>${source.code}</code></pre>