earldouglas

Real-World Functional Programming

May 28, 2014

This code is a companion to the APIcon presentation Real-World Functional Programming by @jearldouglas and @kelleyrobinson. The slides are available here.

In this code, we compare imperative and functional implementations of a withdraw function that might be used in a banking ATM.

Imperative transactions

DrBoolean

import State, {get, put, modify} from 'fantasy-states'
import {prop, compose, map, chain, merge, always} from 'ramda'


// Unfortunately Binary Gendered Baby Page
//==========================================

const babies = [{id: 2, name: 'Anjali', sex: 'F'}, {id: 3, name: 'Antonio', sex: 'M'}]

// isFemale :: Baby -> Bool

JuanJo4

/* 
    Node.js, express, oauth example using Twitters API
    
    Install Dependencies:
        npm install express
        npm install oauth
    
    Create App File:
        Save this file to app.js
    

joshj

/* 
    Node.js, express, oauth example using Twitters API
    
    Install Node.js:
        curl -0 http://nodejs.org/dist/v0.6.11/node-v0.6.11.tar.gz
        tar -zxf node-v0.6.11.tar.gz
        cd node-v0.6.11
        ./configure
        make
        make install

goodwill

[Install]
WantedBy=multi-user.target

[Unit]
Description=Google Cloud Compute Engine SQL Proxy
Requires=networking.service
After=networking.service

[Service]
Type=simple

isaacs

# Hello, and welcome to makefile basics.
#
# You will learn why `make` is so great, and why, despite its "weird" syntax,
# it is actually a highly expressive, efficient, and powerful way to build
# programs.
#
# Once you're done here, go to
# http://www.gnu.org/software/make/manual/make.html
# to learn SOOOO much more.

6174

 //http://stackoverflow.com/questions/105034/how-to-create-a-guid-uuid-in-javascript
 Math.random().toString(36).substring(2, 15) + Math.random().toString(36).substring(2, 15);

vlucas

'use strict';

const crypto = require('crypto');

const ENCRYPTION_KEY = process.env.ENCRYPTION_KEY; // Must be 256 bits (32 characters)
const IV_LENGTH = 16; // For AES, this is always 16

function encrypt(text) {
 let iv = crypto.randomBytes(IV_LENGTH);
 let cipher = crypto.createCipheriv('aes-256-cbc', Buffer.from(ENCRYPTION_KEY), iv);

ryin

#!/bin/bash

# Script for installing tmux on systems where you don't have root access.
# tmux will be installed in $HOME/local/bin.
# It's assumed that wget and a C/C++ compiler are installed.

# exit on error
set -e

TMUX_VERSION=1.8

staltz

The introduction to Reactive Programming you've been missing

(by @andrestaltz)

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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.

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