notheotherben

format = """
[\uE0B6](fg:#1C4961)[$directory](bg:#1C4961)[\uE0B0](fg:#1C4961 bg:#2F79A1)$git_branch[\uE0B0](fg:#2F79A1 bg:#3A95C7)$git_status[\uE0B0](#3A95C7 bg:#40A9E0)$time[\uE0B0](#40A9E0 bg:none) $all$character """

add_newline = true

[directory]
style = "bg:#1C4961 fg:white"

[git_branch]
format = "[ $symbol$branch ]($style)"

reborg

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

ohanhi

Learning FP the hard way: Experiences on the Elm language

by Ossi Hanhinen, @ohanhi

with the support of Futurice 💚.

Licensed under CC BY 4.0.

Editorial note

Integralist

• defprotocol: defines an interface
• deftype: create a bare-bones object which implements a protocol
• defrecord: creates an immutable persistent map which implements a protocol

Typically you'll use defrecord (or even a basic map);
unless you need some specific Java inter-op,
where by you'll want to use deftype instead.

Note: defprotocol allows you to add new abstractions in a clean way Rather than (like OOP) having polymorphism on the class itself,

josephspurrier

/*
********************************************************************************
Golang - Asterisk and Ampersand Cheatsheet
********************************************************************************

Also available at: https://play.golang.org/p/lNpnS9j1ma

Allowed:
--------
p := Person{"Steve", 28} 	stores the value

staltz

The introduction to Reactive Programming you've been missing

(by @andrestaltz)

---

This tutorial as a series of videos

If you prefer to watch video tutorials with live-coding, then check out this series I recorded with the same contents as in this article: Egghead.io - Introduction to Reactive Programming.

---

raineorshine

General Tip

"The trick is to catch exceptions at the proper layer, where your program can either meaningfully recover from the exception and continue without causing further errors, or provide the user with specific information, including instructions on how to recover from the error. When it is not practical for a method to do either of these, simply let the exception go so it can be caught later on and handled at the appropriate level."

Resources

Advantages of Exceptions
Excellent example of separating error-handling code from program logic

Three Rules for Effective Exception Handling
Longer explanation and case study of exception use, including the basic principles of "throw early" and "catch late". Clear and thorough.

ckirkendall

(use '[clojure.core.match :only [match]])

(defn evaluate [env [sym x y]]
  (match [sym]
    ['Number]   x
    ['Add]      (+ (evaluate env x) (evaluate env y))
    ['Multiply] (* (evaluate env x) (evaluate env y))
    ['Variable] (env x)))
    
(def environment {"a" 3, "b" 4, "c" 5})

ghoseb

;;
;; NS CHEATSHEET
;;
;; * :require makes functions available with a namespace prefix
;;  and optionally can refer functions to the current ns.
;;
;; * :import refers Java classes to the current namespace.
;;
;; * :refer-clojure affects availability of built-in (clojure.core)
;;   functions.