| function maybe(value) { | |
| var obj = null; | |
| function isEmpty() { return value === undefined || value === null } | |
| function nonEmpty() { return !isEmpty() } | |
| obj = { | |
| map: function (f) { return isEmpty() ? obj : maybe(f(value)) }, | |
| getOrElse: function (n) { return isEmpty() ? n : value }, | |
| isEmpty: isEmpty, | |
| nonEmpty: nonEmpty | |
| } |
| Latency Comparison Numbers (~2012) | |
| ---------------------------------- | |
| L1 cache reference 0.5 ns | |
| Branch mispredict 5 ns | |
| L2 cache reference 7 ns 14x L1 cache | |
| Mutex lock/unlock 25 ns | |
| Main memory reference 100 ns 20x L2 cache, 200x L1 cache | |
| Compress 1K bytes with Zippy 3,000 ns 3 us | |
| Send 1K bytes over 1 Gbps network 10,000 ns 10 us | |
| Read 4K randomly from SSD* 150,000 ns 150 us ~1GB/sec SSD |
| require.config({ | |
| baseUrl: '/backbone-tests/', | |
| paths: { | |
| 'jquery' : '/app/libs/jquery', | |
| 'underscore' : '/app/libs/underscore', | |
| 'backbone' : '/app/libs/backbone', | |
| 'mocha' : 'libs/mocha', | |
| 'chai' : 'libs/chai', | |
| 'chai-jquery' : 'libs/chai-jquery', | |
| 'models' : '/app/models' |
This article has been given a more permanent home on my blog. Also, since it was first written, the development of the Promises/A+ specification has made the original emphasis on Promises/A seem somewhat outdated.
Promises are a software abstraction that makes working with asynchronous operations much more pleasant. In the most basic definition, your code will move from continuation-passing style:
getTweetsFor("domenic", function (err, results) {
// the rest of your code goes here.
| <html> | |
| <head> | |
| <!-- | |
| In this example, I started with the 5-minute example provided by Google | |
| on the following page: | |
| https://developers.google.com/drive/ | |
| I modified the example code, so that I could write the following |
| package main | |
| import ( | |
| "log" | |
| "net/http" | |
| ) | |
| func redirect(w http.ResponseWriter, r *http.Request) { | |
| http.Redirect(w, r, "http://www.google.com", 301) |
| -- a little flame in a functional style | |
| function particle(step, style, t) | |
| local newStyle = step(style, t) | |
| return { | |
| style = newStyle, | |
| next = function() | |
| return particle(step, newStyle, t + 1) | |
| end | |
| } |
| // Just before switching jobs: | |
| // Add one of these. | |
| // Preferably into the same commit where you do a large merge. | |
| // | |
| // This started as a tweet with a joke of "C++ pro-tip: #define private public", | |
| // and then it quickly escalated into more and more evil suggestions. | |
| // I've tried to capture interesting suggestions here. | |
| // | |
| // Contributors: @r2d2rigo, @joeldevahl, @msinilo, @_Humus_, | |
| // @YuriyODonnell, @rygorous, @cmuratori, @mike_acton, @grumpygiant, |
| // Start `node d3-server.js` | |
| // Then visit http://localhost:1337/ | |
| // | |
| var d3 = require('d3'), | |
| http = require('http') | |
| http.createServer(function (req, res) { | |
| // Chrome automatically sends a requests for favicons | |
| // Looks like https://code.google.com/p/chromium/issues/detail?id=39402 isn't | |
| // fixed or this is a regression. |
| license: apache-2.0 |
