<feedxmlns="http://www.w3.org/2005/Atom"><title>LEdoian's Blog</title><linkhref="https://blog.ledoian.cz/"rel="alternate"></link><linkhref="https://blog.ledoian.cz/feeds/all.atom.xml"rel="self"></link><id>https://blog.ledoian.cz/</id><updated>2024-05-21T17:03:00+02:00</updated><entry><title>Hello, I'm agender</title><linkhref="https://blog.ledoian.cz/hello-im-agen.html"rel="alternate"></link><published>2024-05-21T17:03:00+02:00</published><updated>2024-05-21T17:03:00+02:00</updated><author><name>LEdoian</name></author><id>tag:blog.ledoian.cz,2024-05-21:/hello-im-agen.html</id><summarytype="html"><p>Hell yeah, a coming out!</p>
<feedxmlns="http://www.w3.org/2005/Atom"><title>LEdoian's Blog</title><linkhref="https://blog.ledoian.cz/"rel="alternate"></link><linkhref="https://blog.ledoian.cz/feeds/all.atom.xml"rel="self"></link><id>https://blog.ledoian.cz/</id><updated>2024-09-09T16:28:00+02:00</updated><entry><title>Using Gleam in HTML with as little JavaScript knowledge as possible</title><linkhref="https://blog.ledoian.cz/using-gleam-in-html-low-js.html"rel="alternate"></link><published>2024-09-09T16:28:00+02:00</published><updated>2024-09-09T16:28:00+02:00</updated><author><name>LEdoian</name></author><id>tag:blog.ledoian.cz,2024-09-09:/using-gleam-in-html-low-js.html</id><summarytype="html"><p>I've been looking at the <a class="reference external" href="https://gleam.run">Gleam language</a> recently. Among other features, it can be compiled to JavaScript, and thus presumably used on web frontend. I wanted to try that. This is a short tutorial on how to do that with little idea how JavaScript is supposed to work.</p>
<p>My initial …</p></summary><contenttype="html"><p>I've been looking at the <a class="reference external" href="https://gleam.run">Gleam language</a> recently. Among other features, it can be compiled to JavaScript, and thus presumably used on web frontend. I wanted to try that. This is a short tutorial on how to do that with little idea how JavaScript is supposed to work.</p>
<p>My initial JS knowledge: <tt class="docutils literal">alert(3)</tt>, <tt class="docutils literal">onclick</tt> and some basic selectors, i.e. the little stuff that is useful to add minor interactivity to HTML pages and implement trivial ViolentMonkey scripts. Namely: I have no knowledge about modules and whatnot, and this post is just a result of my trial-and-error attempt at embedding my Gleam. I succeeded, but still have no idea what I am doing :-)</p>
<div class="section" id="my-code">
<h2>My code</h2>
<p>Let's start with some trivial code, in <tt class="docutils literal">src/lol.gleam</tt> (in a project initialised with <tt class="docutils literal">gleam new lol</tt> and the <tt class="docutils literal">repeatedly</tt> package added with <tt class="docutils literal">gleam add repeatedly</tt>):</p>
<p>This snippet has many of the basic stuff I might need in future: it does some io, it uses another package <a class="footnote-reference" href="#stdlib-package" id="footnote-reference-1">[1]</a>, it returns data I will want to show. At first I am mostly interested in multiplatform stuff (i.e. running also on the BEAM backend), so I don't want to use any DOM frameworks at first, though I will mention some of the ways later in the post.</p>
<p>So, build this for JavaScript: <tt class="docutils literal">gleam build <span class="pre">--target</span> javascript</tt>, and <em>stuff happens</em>. It is not very clear what to do now, but <tt class="docutils literal"><span class="pre">grep``ping</span> through the ``build/</tt> directory shows that the built code lives in <tt class="docutils literal">build/dev/javascript/lol/lol.mjs</tt>.</p>
<p>Here comes the fun part: the code is in JavaScript <em>module</em>, not plain code. That comes with several surprises:
- It can only be imported from other modules, not by “plain” code in global scope
- Due to CORS, imports only work with network schemes, not with the <tt class="docutils literal"><span class="pre">file://</span></tt> one
- Due to scoping, I have not found a way of using the functions from devtools console</p>
<p>Big wins for the platform /s, but we have to live with that, so let's try to write the respective HTML for this. I put that in <tt class="docutils literal">main.html</tt> in the project root, but it does not probably matter. The code:</p>
&lt;!-- the “binding” to our Gleam code. This probably needs to be at the end of the page, since it needs to be able to use the selectors. --&gt;
&lt;script type=module&gt; //It has to be a module to allow imports
import * as lol from &quot;./build/dev/javascript/lol/lol.mjs&quot;;
// Set the text of one element to the computed stuff:
let par = document.getElementById('uwu');
par.innerText = lol.get_greeting();
// Let's have an interactive button (I love the come-from pattern, but using `onclick` would be even trickier…)
let butt = document.getElementById('butt');
butt.addEventListener('click', lol.say_hello);
// Apparently, the `main` function does not get run automatically, so call that explicitly.
lol.main();
&lt;/script&gt;
&lt;/body&gt;
&lt;/html&gt;
</pre>
<p>Shoutout to <a class="reference external" href="https://stackoverflow.com/questions/53630310/use-functions-defined-in-es6-module-directly-in-html">the person who asked the same question on StackOverflow</a>. From this point on, we only need a HTTP server; luckily, Python has one in stdlib, so just calling <tt class="docutils literal">python3 <span class="pre">-m</span> http.server 12312</tt> in the project root lets us load <tt class="docutils literal"><span class="pre">http://localhost:12312/main.html</span></tt> and see our page.</p>
<h2>Next steps, alternatives et cetera</h2>
<p>When developing web frontend in Gleam, the more common way is using a framework like <a class="reference external" href="https://hexdocs.pm/lustre/index.html">Lustre</a> or at least a DOM library (there are <a class="reference external" href="https://packages.gleam.run/?search=dom">several</a>, I have no idea how mature those are). I did not go this route yet, because I am more interested in using backend-agnostic Gleam code from JavaScript and don't mind writing the trivial bindings in JavaScript. <a class="footnote-reference" href="#netzpevnik-gleam" id="footnote-reference-2">[2]</a></p>
<p>Also, a common thing to do is using a minifier+bundler like <a class="reference external" href="https://hexdocs.pm/esgleam/index.html">esgleam</a> (it uses <a class="reference external" href="https://esbuild.github.io/">esbuild</a> under the hood), so that the whole project is in one file. I don't think I need that now (having the JS be readable is more important to me atm and I don't want to complicate things further), but there is at least <a class="reference external" href="https://erikarow.land/notes/esgleam-embed">one tutorial</a> on how to do that.</p>
<p>Also, during writing of this article I realised Gleam can run all the JS code from itself, so I could have a <tt class="docutils literal">js_main</tt> function that would bind the HTML from Gleam itself. But this is probably more readable and separated anyway.</p>
<tr><td class="label"><a class="fn-backref" href="#footnote-reference-1">[1]</a></td><td>Well, as far as I understand it, Gleam's stdlib is actually just another package anyway.</td></tr>
<tr><td class="label"><a class="fn-backref" href="#footnote-reference-2">[2]</a></td><td>I will probably use some kind of framework eventually as a part of <a class="reference external" href="https://gitea.ledoian.cz/LEdoian/netzpevnik">netzpevnik</a>, but I am exploring the technologies that will be involved, so I want to keep stuff simple.</td></tr>
</tbody>
</table>
</div>
</content><categoryterm="programming"></category><categoryterm="gleam"></category><categoryterm="software"></category><categoryterm="web"></category></entry><entry><title>Hello, I'm agender</title><linkhref="https://blog.ledoian.cz/hello-im-agen.html"rel="alternate"></link><published>2024-05-21T17:03:00+02:00</published><updated>2024-05-21T17:03:00+02:00</updated><author><name>LEdoian</name></author><id>tag:blog.ledoian.cz,2024-05-21:/hello-im-agen.html</id><summarytype="html"><p>Hell yeah, a coming out!</p>
<p>Important: Please, read this article <em>in full</em> and do not just skim it. There
is no TL;DR, I don't think any reasonable summary of this post can be made
without me misrepresenting myself. Alternatively, please just skip this article
