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@levand
levand / data-modeling.md
Last active January 23, 2026 15:30
Advice about data modeling in Clojure

Since it has come up a few times, I thought I’d write up some of the basic ideas around domain modeling in Clojure, and how they relate to keyword names and Specs. Firmly grasping these concepts will help us all write code that is simpler, cleaner, and easier to understand.

Clojure is a data-oriented language: we’re all familiar with maps, vectors, sets, keywords, etc. However, while data is good, not all data is equally good. It’s still possible to write “bad” data in Clojure.

“Good” data is well defined and easy to read; there is never any ambiguity about what a given data structure represents. Messy data has inconsistent structure, and overloaded keys that can mean different things in different contexts. Good data represents domain entities and a logical model; bad data represents whatever was convenient for the programmer at a given moment. Good data stands on its own, and can be reasoned about without any other knowledge of the codebase; bad data is deeply and tightly coupled to specific generating and

@reborg
reborg / rich-already-answered-that.md
Last active February 18, 2026 01:27
A curated collection of answers that Rich gave throughout the history of Clojure

Rich Already Answered That!

A list of commonly asked questions, design decisions, reasons why Clojure is the way it is as they were answered directly by Rich (even when from many years ago, those answers are pretty much valid today!). Feel free to point friends and colleagues here next time they ask (again). Answers are pasted verbatim (I've made small adjustments for readibility, but never changed a sentence) from mailing lists, articles, chats.

How to use:

  • The link in the table of content jumps at the copy of the answer on this page.
  • The link on the answer itself points back at the original post.

Table of Content

@gbaman
gbaman / HowToOTGFast.md
Last active March 30, 2026 22:42
Simple guide for setting up OTG modes on the Raspberry Pi Zero, the fast way!

Setting up Pi Zero OTG - The quick way (No USB keyboard, mouse, HDMI monitor needed)

More details - http://blog.gbaman.info/?p=791

For this method, alongside your Pi Zero, MicroUSB cable and MicroSD card, only an additional computer is required, which can be running Windows (with Bonjour, iTunes or Quicktime installed), Mac OS or Linux (with Avahi Daemon installed, for example Ubuntu has it built in).
1. Flash Raspbian Jessie full or Raspbian Jessie Lite onto the SD card.
2. Once Raspbian is flashed, open up the boot partition (in Windows Explorer, Finder etc) and add to the bottom of the config.txt file dtoverlay=dwc2 on a new line, then save the file.
3. If using a recent release of Jessie (Dec 2016 onwards), then create a new file simply called ssh in the SD card as well. By default SSH i

@saiberz
saiberz / compojure.clj
Last active October 23, 2024 07:41
Introduction to Compojure
Foreword
========
This is a very rough draft of the tutorial I'm going to put on
compojure.org. It's not complete, but it covers most of the basics.
There's a possibility some of the terminology (such as handlers and
routes) might change, but I'll let you know if it does. The technical
content, however, should be accurate and up to date.
Criticism is very welcome; I'd like to know if anything is unclear or
@bobbygrace
bobbygrace / trello-css-guide.md
Last active September 27, 2025 06:29
Trello CSS Guide

Hello, visitors! If you want an updated version of this styleguide in repo form with tons of real-life examples… check out Trellisheets! https://github.com/trello/trellisheets


Trello CSS Guide

“I perfectly understand our CSS. I never have any issues with cascading rules. I never have to use !important or inline styles. Even though somebody else wrote this bit of CSS, I know exactly how it works and how to extend it. Fixes are easy! I have a hard time breaking our CSS. I know exactly where to put new CSS. We use all of our CSS and it’s pretty small overall. When I delete a template, I know the exact corresponding CSS file and I can delete it all at once. Nothing gets left behind.”

You often hear updog saying stuff like this. Who’s updog? Not much, who is up with you?

@favila
favila / async-util.clj
Created November 28, 2014 17:06
Some missing pieces of core.async. as-transducer: Make a transducer function easily without Clojure 1.7. go-pipe: async/pipe, but returns the go-loop. fast-pipeline-blocking: faster than async/pipeline-blocking, but unordered results. blocking-consumer: consume a channel with multiple worker threads.
(ns favila.async-util
"Some missing pieces of core.async.
as-transducer: Make a transducer function easily without Clojure 1.7.
go-pipe: async/pipe, but returns the go-loop.
fast-pipeline-blocking: faster than async/pipeline-blocking, but unordered results.
blocking-consumer: consume a channel with multiple worker threads."
(:require [clojure.core.async :as async
:refer [go go-loop <! >! <!! >!! close! take! put! chan]]))
@daveray
daveray / hystrix-clj-snippets.clj
Last active August 29, 2015 14:04
hystrix clj snippets
(def user-prefs
{:type :command
:group-key :Cassandra
:command-key :GetUserPreferences
:run-fn (fn [user-id] ... do request ...)
:fallback-fn (fn [user-id] { ... default prefs ...})
:cache-key-fn (fn [user-id] (str user-id)) })
(require '[com.netflix.hystrix.core :as hystrix])
@john2x
john2x / 00_destructuring.md
Last active March 14, 2026 08:35
Clojure Destructuring Tutorial and Cheat Sheet

Clojure Destructuring Tutorial and Cheat Sheet

(Related blog post)

Simply put, destructuring in Clojure is a way extract values from a datastructure and bind them to symbols, without having to explicitly traverse the datstructure. It allows for elegant and concise Clojure code.

Vectors and Sequences

# config/routes.rb
resources :documents do
scope module: 'documents' do
resources :versions do
post :restore, on: :member
end
resource :lock
end
end