CMCDragonkai

Understanding the Memory Layout of Linux Executables

Required tools for playing around with memory:

• hexdump
• objdump
• readelf
• xxd
• gcore

djspiewak

Explaining Miles's Magic

Miles Sabin recently opened a pull request fixing the infamous SI-2712. First off, this is remarkable and, if merged, will make everyone's life enormously easier. This is a bug that a lot of people hit often without even realizing it, and they just assume that either they did something wrong or the compiler is broken in some weird way. It is especially common for users of scalaz or cats.

But that's not what I wanted to write about. What I want to write about is the exact semantics of Miles's fix, because it does impose some very specific assumptions about the way that type constructors work, and understanding those assumptions is the key to getting the most of it his fix.

For starters, here is the sort of thing that SI-2712 affects:

def foo[F[_], A](fa: F[A]): String = fa.toString

dmvaldman

Promises as EventEmitters

I was trying to understand JavaScript Promises by using various libraries (bluebird, when, Q) and other async approaches.

I read the spec, some blog posts, and looked through some code. I learned how to

mkaz

10 Scala One Liners to Impress Your Friends

Here are 10 one-liners which show the power of scala programming, impress your friends and woo women; ok, maybe not. However, these one liners are a good set of examples using functional programming and scala syntax you may not be familiar with. I feel there is no better way to learn than to see real examples.

Updated: June 17, 2011 - I'm amazed at the popularity of this post, glad everyone enjoyed it and to see it duplicated across so many languages. I've included some of the suggestions to shorten up some of my scala examples. Some I intentionally left longer as a way for explaining / understanding what the functions were doing, not necessarily to produce the shortest possible code; so I'll include both.

1. Multiple Each Item in a List by 2

The map function takes each element in the list and applies it to the corresponding function. In this example, we take each element and multiply it by 2. This will return a list of equivalent size, compare to o

soultech67

# this is an example of: config/application.rb

require 'rails/all'
require 'rspec-rails'

# Require the gems listed in Gemfile, including any gems
# you've limited to :test, :development, or :production.
Bundler.require(*Rails.groups)

module UnicornHostedRailsApp

squarism

Tabs and Windows

Function	Shortcut
New Tab	⌘ + T
Close Tab or Window	⌘ + W (same as many mac apps)
Go to Tab	⌘ + Number Key (ie: ⌘2 is 2nd tab)
Go to Split Pane by Direction	⌘ + Option + Arrow Key
Cycle iTerm Windows	⌘ + backtick (true of all mac apps and works with desktops/mission control)

paulirish

What forces layout / reflow

All of the below properties or methods, when requested/called in JavaScript, will trigger the browser to synchronously calculate the style and layout*. This is also called reflow or layout thrashing, and is common performance bottleneck.

Generally, all APIs that synchronously provide layout metrics will trigger forced reflow / layout. Read on for additional cases and details.

Element APIs

Getting box metrics

• elem.offsetLeft, elem.offsetTop, elem.offsetWidth, elem.offsetHeight, elem.offsetParent

theRemix

MongoDB Practice

MongoDB Exercise in mongo shell

Connect to a running mongo instance, use a database named mongo_practice.

Document all your queries in a javascript file to use as a reference.

Insert Documents

pbakondy

// http://speakingjs.com/es5/ch17.html#code_copyOwnPropertiesFrom

// To create an identical copy of an object, you need to get two things right:
// - The copy must have the same prototype as the original.
// - The copy must have the same properties, with the same attributes as the original.


function copyObject(orig, deep) {
    // 1. copy has same prototype as orig
    var copy = Object.create(Object.getPrototypeOf(orig));

brianpetro

Because I couldn't find these with a quick Google search on 28 April 2015:

Usage:
  rails new APP_PATH [options]

Options:
  -r, [--ruby=PATH]                                      # Path to the Ruby binary of your choice
                                                         # Default: /home/brian/.rvm/rubies/ruby-2.2.0/bin/ruby
  -m, [--template=TEMPLATE]                              # Path to some application template (can be a filesystem path or URL)
      [--skip-gemfile], [--no-skip-gemfile]              # Don't create a Gemfile