sethkrasnianski

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

sethkrasnianski

/** 
 * jQuery 2.1.3's parseHTML (without scripts options).
 * Unlike jQuery, this returns a DocumentFragment, which is more convenient to insert into DOM.
 * MIT license.
 * 
 * If you only support Edge 13+ then try this:
    function parseHTML(html, context) {
        var t = (context || document).createElement('template');
            t.innerHTML = html;
        return t.content.cloneNode(true);

sethkrasnianski

#!/usr/bin/env sh

# Multiple vulnerabilities have been disclosed in RubyGems:
# https://www.ruby-lang.org/en/news/2018/02/17/multiple-vulnerabilities-in-rubygems/
#
# If you're an Rbenv user, here's any easy one-liner to upgrade to a 
# safe version of Rubygems (2.7.6 or later) for each installed Ruby version:

for i in $( rbenv versions --bare ); do RBENV_VERSION=$i gem update --system && echo "\n$(ruby -v) using rubygems $(gem --version)\n"; done

sethkrasnianski

Automatic build versions from git in Xcode (and other goodies)

Installation procedure for pre-build actions to automatically populate Xcode Info.plist with dynamic data.

1. Xcode Scheme pre-action

Edit Xcode Scheme and add a pre-action script. Copy the contents of preaction.sh into the pre-action script box.

sethkrasnianski

Recently, I had a staging database on Heroku that was running on the Ronin database (which was originally the lowest-sized DB you could get at Heroku). Since they added two new options, Crane and Kappa, we wanted to take advantage of the cost savings. Here's how you can migrate your Ronin DB to Crane (or any other plan).

The old database was named BROWN while the new one is CRIMSON. You can determine this by running:

heroku pg:info --app myapp-staging

1. Add Crane database

    heroku addons:add heroku-postgresql:crane --app myapp-staging
   

heroku pg:wait --app myapp-staging

sethkrasnianski

#!/bin/bash

# I made this script to convert SVG icons for an iOS app into PNG.
# The script will create icons in 3 sizes for different screen DPIs.

find . -type f -name "*.svg" | while read f
do
    FILENAME="${f%.*}"
    echo '---'
    inkscape -W "$FILENAME.svg"

sethkrasnianski

Types

A type is a collection of possible values. An integer can have values 0, 1, 2, 3, etc.; a boolean can have values true and false. We can imagine any type we like: for example, a HighFive type that allows the values "hi" or 5, but nothing else. It's not a string and it's not an integer; it's its own, separate type.

Statically typed languages constrain variables' types: the programming language might know, for example, that x is an Integer. In that case, the programmer isn't allowed to say x = true; that would be an invalid program. The compiler will refuse to compile it, so we can't even run it.

sethkrasnianski

Hi Nicholas,

I saw you tweet about JSX yesterday. It seemed like the discussion devolved pretty quickly but I wanted to share our experience over the last year. I understand your concerns. I've made similar remarks about JSX. When we started using it Planning Center, I lead the charge to write React without it. I don't imagine I'd have much to say that you haven't considered but, if it's helpful, here's a pattern that changed my opinion:

The idea that "React is the V in MVC" is disingenuous. It's a good pitch but, for many of us, it feels like in invitation to repeat our history of coupled views. In practice, React is the V and the C. Dan Abramov describes the division as Smart and Dumb Components. At our office, we call them stateless and container components (view-controllers if we're Flux). The idea is pretty simple: components can'

sethkrasnianski

(ns wl.core 
	(:use compojure.core, aleph.core, aleph.http, hiccup.core, hiccup.page-helpers)
	(:require [compojure.route :as route])
	(:gen-class))

(def broadcast-channel (channel))

(defn chat-handler [ch handshake]
  (receive ch
    (fn [name]

sethkrasnianski

tmux shortcuts & cheatsheet

start new:

tmux

start new with session name:

tmux new -s myname