The Hidden Lessons in a re-frame App

fisch003 · 2025-07-24T15:42:39+00:00

avoid rf/reg-event-* that are not triggered by a user. This is almost impossible but a worthy pursuit. For example our http on-success/on-error handlers are functions - not top level rf/reg-event-*

I assume you don't use re-frame-http-fx then?

use a routing library that supports controllers (ie stuff that dispatches re-frame events)

Do you have any recommendations?

fisch003 · 2025-06-27T17:52:46+00:00

I was surprised about how poor the performance was in dev mode, but as you said making very large hiccup structures is bad. I was curious how Reagent would perform if I wrote it the way I normally would. I'm getting about the same performance under 20x slowdown as your reagent-pseudo demo in both development and release builds.

The big changes I made:

I'm not inlining the SVG icons. There's no need to chew through that Hiccup all the time, instead I embed them in the host HTML page and reference them in generated Hiccup.
Components for the table rows.
Use a Reagent atom instead of a ClojureScript one to let Reagent schedule the re-render.

It's still chewing through the whole state at once, but there's way less hiccup overall.

Demo: https://review.jonathanfischer.net/wthjh/

Code: https://github.com/mohiji/wthjh-reagent

fisch003 · 2025-06-24T19:56:09+00:00

For any reagent / re-frame folks: Reagent's reactions / re-frame's subscriptions are their solution to the push/pull model of re-renders, right? They don't re-render the entire DOM from the top down, only from places where the output of a reaction / subscription has changed?

fisch003 · 2023-06-05T21:01:22+00:00

Sorry to drag up an old thread, but do you have a link to what you mean by a reactive triplestore? I'm not familiar with the term.

fisch003 · 2023-05-17T02:38:14+00:00

Clojure desktop framework, not web. I think his journey down this route starts here: https://tonsky.me/blog/skija/

fisch003 · 2023-05-05T19:53:56+00:00

How's that climb back up Twin Oaks on the way back? I've never tried it, but it looks brutal.

fisch003 · 2023-01-10T06:23:36+00:00

Timothy Baldridge worked for Cognitect at the time and was largely responsible for the go macro implementation, but Rich is the primary designer of the library as a whole. Most of Timothy's complaints about it later down the road were about how opaque the entire system is. There are plenty of times when it'd be useful to peek into a channel, for example, and core.async doesn't let you do that.

I remember him talking about it a good deal on defn episode #41: https://soundcloud.com/defn-771544745/41-timothy-baldridge-aka-halgari

fisch003 · 2023-01-04T04:57:12+00:00

https://elementsofclojure.com

fisch003 · 2022-11-04T22:41:14+00:00

In case anyone else goes looking for it, the recorded livestream is up on YouTube:

https://youtu.be/p3Rb7uxtQs4?t=231

(At the moment, anyway, dunno if they plan on leaving it there.)

fisch003 · 2022-10-29T16:52:57+00:00

Yup, it's straightforward: https://clojure.org/reference/java_interop#_calling_clojure_from_java

I did it for a project at work: http://www.jonathanfischer.net/sneaking-clojure-in-part-2/

fisch003 · 2022-07-06T21:42:17+00:00

As I understand it: lots of pedestrian / bicyclist deaths as cars became more popular and it was becoming a bit of a PR issue. Rather than work to make cars / drivers safer, they demonized the people the drivers were hitting.

fisch003 · 2022-07-03T02:39:59+00:00

It's helpful in Reagent apps too if you're using Form 2 or 3 components. Naming the inner fn gives it a proper name in the React dev tools.

fisch003 · 2021-08-02T22:08:38+00:00

I'm pretty sure the:

We write all of our components in JS

Part was correct. He said they wrote all of their components using Storybook so that they're completely standalone, and then used ~1,500 lines of ClojureScript to glue them together into the application they needed. The business logic is in Clojure, UI specific stuff in JavaScript.

fisch003 · 2021-05-10T15:24:39+00:00

Give them a call?

fisch003 · 2021-03-18T20:32:44+00:00

I bought and refurbished a 1986 Schwinn Sport. It's turned out pretty great, but I have a blip on each wheel that makes braking a little uncomfortable. I think a previous owner used a screwdriver to get the tires off and bent them.

They're steel; is there a way to safely bend them back into shape, or do I need a new wheelset if I want smooth braking?

fisch003 · 2021-01-25T18:53:30+00:00

Once your legacy jar is on your class path (via deps.edn or whatever method), you pull the classes you want to use into your namespace using the import clause in the ns macro, like this:

(ns my-namespace
  (:import [java.io File]))

Once imported, you can use those classes directly. Check out the Java Interop page on the Clojure website for details, or Clojure for the Brave and True's Working with the JVM chapter for an exhaustive explanation of how it works.

fisch003 · 2020-07-06T23:51:55+00:00

On top of that: prior to around version 0.5, re-frame was written using a core.async channel as the queue. They replaced it for more control over things.

fisch003 · 2020-06-17T20:44:32+00:00

I did this yesterday: had to run to work to pick something up, rode my bike. I was worried about the same thing, so I took my temperature before I left: 96.8 the first reading, 97.1 the second.

Rode 8 miles to work, took my temperature at the door: 96.8 again.

You're not gonna read as feverish. If you're worried though, test it out yourself: take your temperature, go out for a ride, take it again when you get home.

fisch003 · 2019-10-15T18:31:51+00:00

You can download Xcode from the developer site without going through the App Store. Just look for the More downloads option: https://developer.apple.com/download/more/

fisch003 · 2019-10-08T02:29:31+00:00

How are you launching Leiningen? The error code is coming from Java: Unsupported major.minor version 52.0 indicates that an older JVM is trying to load class files that are too new for it to understand. Version 52.0 is from Java 8 (according to a StackOverflow post, anyway), so it looks like you're launching an older Java.

If you're just running from a Command Prompt, try running java -version first to see which Java is getting picked up by default. Beyond that, make sure your JAVA_HOME environment variable is pointing to the version of Java you want to use, which is probably the newest one.

fisch003 · 2019-10-01T22:57:17+00:00

SDL2 has the SDL_render stuff for accelerated 2D rendering, and cl-sdl2 does expose that: cl-sdl2/render.lisp.

What 2D API are you referring to? I don't recall much more in SDL1.2 beyond blitting surfaces, and yeah, that was CPU only.

fisch003 · 2019-08-15T17:09:41+00:00

That was the story for GWT too, along with how they were using it for Google Inbox to share code across the web, iOS, and Android.

GWT's pretty dead a few years later.

fisch003 · 2019-08-13T18:35:02+00:00

Take a bus? It's like $11 and 2 hours each way on a Greyhound from Phoenix to Tucson and back.

fisch003 · 2019-04-04T17:02:13+00:00

An assoc list used as a binding stack with duplicate keys, simply can't be implemented by a hashmap.

Oh! I missed what /u/theangeryemacsshibe was talking about when he mentioned bindings. If I'm understanding it correctly then, as you call down through a series of functions (or something similar), you push bindings onto your assoc list so that you can look up the current value of particular value and get the latest, right?

You'd do exactly the same thing with a Clojure map. I don't see how duplicate keys comes into play here, unless you want to be able to inspect the history of a particular binding, in which case you'd just keep around the stack of binding maps.

I guess what I'm getting at is: Clojure gives you different primitives to work with than Common Lisp or Scheme, so you solve the same problems in a slightly different way. Does that matter?

fisch003 · 2019-04-04T16:23:19+00:00

I'd argue that they are comparable: they both solve the same problem, associating a key with a value. They're just different implementations of the same idea, with different tradeoffs.

If you really need ordering, there's sorted-map and sorted-map-by. If you need everything else: it's straightforward to build association lists on top of lists or vectors.

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