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written, the development of the Promises/A+ specification has made the original emphasis on Promises/A seem somewhat outdated.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.
This is just a small post in response to [this tweet][tweet] by Julien Pauli (who by the way is the release manager for PHP 5.5). In the tweet he claims that objects use more memory than arrays in PHP. Even though it can be like that, it's not true in most cases. (Note: This only applies to PHP 5.4 or newer.)
The reason why it's easy to assume that objects are larger than arrays is because objects can be seen as an array of properties and a bit of additional information (like the class it belongs to). And as array + additional info > array it obviously follows that objects are larger. The thing is that in most cases PHP can optimize the array part of it away. So how does that work?
The key here is that objects usually have a predefined set of keys, whereas arrays don't:
| # Original Rails controller and action | |
| class EmployeesController < ApplicationController | |
| def create | |
| @employee = Employee.new(employee_params) | |
| if @employee.save | |
| redirect_to @employee, notice: "Employee #{@employee.name} created" | |
| else | |
| render :new | |
| end |
| #!/bin/bash | |
| brew search librabbitmq | |
| brew install rabbitmq-c | |
| pecl install amqp | |
| # set the path to librabbitmq install prefix [autodetect] : /usr/local/Cellar/rabbitmq-c/0.10.0 | |
| # if it fails follow the following (reference: https://github.com/pdezwart/php-amqp/issues/355#issuecomment-563203121): |