Advanced Ruby

In large programs, especially when heavy abstraction is involved, it's sometimes impossible to tell where your data is coming from. Consider the following situation: a server application takes user input from a client and does some processing. It then offloads some of this processing (for example, resizing an image file) to an external program using the backtick operator. The command passed t…

It's often necessary to make a copy of a value in Ruby. While this may seem simple, and it is for simple objects, as soon as you have to make a copy of a data structure with multiple array or hashes on the same object, you will quickly find there are many pitfalls.

Using hashes to simulate optional named parameters in methods.

There are two forms of command-line options: long form and short form. Both long and short form options take arguments, each a little differently.

Ruby comes equipped with a powerful and flexible tool to parse command-line options, OptionParser. The class is an alternative to GetoptLong for analyzing command line options.

Using OptionParser to parse command line options is a preferable alternative to GetoptLong or looking through ARGV manually. But how do you use it?

A short guide on writing Domain Specific Languages in Ruby.

Knowing how to make quick exceptions to catch and tell the difference between several conditions is a Ruby best practice you can't afford not to know.

Computers are quite good at math or, more precisely, at arithmetic. In fact, technically, that's all a computer can do. However, the numbers computers typically work with are quite limited. On a typical computer, an integer number is represented by a 32-bit binary number. A 32-bit integer can only represent the numbers from about negative 2 billion to positive 2 billion.

Challenges to test your Ruby programming skills.

Debugging Ruby programs using the Ruby debugger.

Running the Ruby profiler to determine which methods are most expensive and which need to be optimized.

Ruby recipes at PLEAC (Programming Language Examples Alike Cookbook), the example programs from the Perl Cookbook re-written in Ruby.

Distributed Ruby, or DRb, is a library that allows you to communicate with remote Ruby objects and programs, using TCP/IP network protocols.

There are several ways to run other programs in Ruby. There is the system> method, backticks, etc. However, they all spawn new processes. If there is nothing left for your Ruby program to do, it has to sit there wasting memory until the launched program finishes. The exec> method fixes this.

Most non-compiled languages have some kind of eval function, which will take a string and execute it as code.

A few tips and tricks to make things a little easier.

You can use eval to run code from a string, but things are not as simple as they seem. The eval method executes code, but where in the program is that code executed?

With RVM installed on your system, it's easy to have many versions of Ruby installed. And, especially if you switch between them often, it's easy to forget which Bash command prompt is using which Ruby version. You can solve this by putting your Ruby version in your Bash prompt.

Creating Ruby gems has always been a bit of a pain. When you get right down to it, it's not a hard thing to do, but it's easy to forget how if you don't do it often enough. There are quite a few gems to help you write other gems, but if you're using Rails 3, there's already a gem on your system that does this: Bundler.

Information on installing, running and contributing to the development of the latest release of Ruby.

Ruby is an extremely flexible language. It's a truly object oriented language, meaning everything is an object that responds to messages. It's also an open language, meaning you can not only add new methods to any class, but replace any method in any class. This has led to something that's at once great, and terrible: monkey patching.

How to install gems from git repositories.

By using the Enumerable module, you can make any of your classes act like Ruby standard collections. All you need to do is implement the 'each' method.

The Ruby garbage collector is a mysterious thing, but it's not very complicated.

Ruby provides an easy way to make unique abbreviations of a set of words.

Base64 is a way to represent any data as an ASCII string. It's used to encode files to send in email or other ASCII-only protocols. Ruby provides a few easy methods to encode and decode Base64 data.

When web developers fail to implement strong password security it's the users that suffer. This primer will teach you what you need to know in order to safely store passwords in a database.

Generating cryptographic hashes, such as MD5 or SHA1 hashes, in Ruby is very easy. Ruby provides two libraries for doing this: a builtin Digest library and access to the OpenSSL library.

Taking a reference to a method doesn't sound like it should be possible. A method cannot exist on its own, right? Right, but Ruby does allow you to easily pair a reference to a method and the object it belongs to.

Weak references store a reference to an object without incrementing the reference counter. This allows you to reference an object and still allow it to be collected by the garbage collector.