Ruby is one of the languages I use on a regular basis. Unfortunately, the proliferation of interpreters and gems can be hard to keep under control. One of my goals with the new system was to improve this process.

This posts documents the commands I executed, for future reference.

Mac OS X 10.7 Ruby Environment

Before we get started, let’s inspect the standard Ruby install that ships with Mac OS X 10.7.

$ which ruby
/usr/bin/ruby

$ gem environment
RubyGems Environment:
- RUBYGEMS VERSION: 1.3.6
- RUBY VERSION: 1.8.7 (2010-01-10 patchlevel 249) [universal-darwin11.0]
- INSTALLATION DIRECTORY: /Library/Ruby/Gems/1.8
- RUBY EXECUTABLE: /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/bin/ruby
- EXECUTABLE DIRECTORY: /usr/bin
- RUBYGEMS PLATFORMS:
- ruby
- universal-darwin-11
- GEM PATHS:
- /Library/Ruby/Gems/1.8
- /Users/jaredhanson/.gem/ruby/1.8
- /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/gems/1.8
- GEM CONFIGURATION:
- :update_sources => true
- :verbose => true
- :benchmark => false
- :backtrace => false
- :bulk_threshold => 1000
- REMOTE SOURCES:
- http://rubygems.org/


Install RVM: Ruby Version Manager

RVM is a tool that allows us to work with multiple Ruby environments, including different interpreter versions and sets of gems.

Install it just as the instructions recommend:

$ bash < <(curl -s https://rvm.beginrescueend.com/install/rvm)


The installation script will output useful messages, explaining exactly what it is doing and offering hints about what to do after installation is complete. The one critical thing to do is source the rvm script, so that the command is available in the shell. I keep this in my dotfiles, so it is always available. You can also source it temporarily in the current shell by executing:

$ source "$HOME/.rvm/scripts/rvm"


Install Ruby

Now that RVM is installed, we can proceed to install local versions of Ruby. To minimize differences, I first install the same version of Ruby shipped with the OS. RVM makes it easy to install and switch to newer version later.

$ rvm install 1.8.7
$ rvm use 1.8.7


Now, the version of Ruby in use is completely isolated from the system.

$ which ruby
/Users/jaredhanson/.rvm/rubies/ruby-1.8.7-p352/bin/ruby
$ which gem
/Users/jaredhanson/.rvm/rubies/ruby-1.8.7-p352/bin/gem


Rake is my most utilized Ruby-based utility, so that is first on my list to install.

$ gem install rake
/Users/jaredhanson/.rvm/rubies/ruby-1.8.7-p352/lib/ruby/1.8/timeout.rb:60: [BUG] Segmentation fault
ruby 1.8.7 (2011-06-30 patchlevel 352) [i686-darwin11.0.1]

Abort trap: 6


Damn.

Install Ruby with GCC 4.2

Mac OS X 10.7 is using an LLVM-based compiler by default, which is causing trouble. Luckily, a solution can be found on Stack Overflow.

RVM makes it easy to remove the broken installation of Ruby:

$ rvm remove 1.8.7


Installing Ruby 1.8.7 with plain (non-LLVM) gcc fixes the issue:

CC=/usr/bin/gcc-4.2 rvm install 1.8.7


Gems can now be installed successfully:

$ gem install rake
Fetching: rake-0.9.2.gem (100%)
Successfully installed rake-0.9.2
1 gem installed
Installing ri documentation for rake-0.9.2...
Installing RDoc documentation for rake-0.9.2...

$ which rake
/Users/jaredhanson/.rvm/gems/ruby-1.8.7-p352/bin/rake


Conclusion

RVM is now installed, and can be used to manage multiple Ruby environments. Additionally, gemsets can be used to manage which sets of gems are available in each environment. This is a much cleaner and more flexible way to manage a Ruby development system.

However, due to time constraints, Chrysalis does not support the latest version of Rake (currently 0.8.3). The 0.8 branch reworked some of the internals, and Chrysalis was developed against 0.7.3. As such, I often need to quickly switch between multiple versions of Rake.

Thankfully, the executable RubyGems places in the bin directory makes this easy. I had long been curious how this works, so I took the time to figure it out.

The executable scripts generated by RubyGems, in this case for Rake, look like the following:

require 'rubygems'
 
version = ">= 0"
 
if ARGV.first =~ /^_(.*)_$/ and Gem::Version.correct? $1 then
  version = $1
  ARGV.shift
end
 
gem 'rake', version
load 'rake'


There is a bit of regular expression magic that works on the first argument to the command, accessed through ARGV.first. The =~ is the positive match operator for regular expressions. If a match is found, a portion of it will be stored in the global variable $1.

The goal of the RubyGems-generated script is to match a user-supplied version number, without interfering with any other arguments the actual script may expect. In order to do so, the version argument is surrounded by underscores. This is enforced by using the ^ and $ as achors for the beginning and end of the string, respectively.

The result of all this is a simple way to switch between versions easily on the command line.

$ rake _0.7.3_ --version
$ rake _0.8.3_ --version


My main motivation for writing these libraries was to get at the build configurations, so convenience methods are provided for reading those. However, a full parse tree is constructed, so any other information can be obtained relatively easily as well.

To install, use the following commands:

> gem install vstudioide
> gem install xcodeide


I’ve long thought that building applications, along with their dependencies, could be easier and more efficient. Chrysalis is my attempt at making it so. I’ve been putting it to use in my projects, and have been pleased with the results.

If you’ve had the same thoughts, check out Chrysalis. There’s plenty of documentation on the site to get you started. The core of initial release is stable, but there are additional features that would be useful. Feel free to send me your feedback and suggestions.

mongrel-soap4r allows you to host SOAP-based web services using Mongrel as the underlying HTTP server. Incoming SOAP messages will be routed to the standard SOAP4R library for processing.

This is the initial release, so it hasn’t been thoroughly tested and the documentation is sparse. But I’ll be remedying these problems, and would appreciate feedback and patches.

To install, execute the usual command:

> gem install mongrel-soap4r

Ruby on Rails dramatically altered the way people build web applications. With the 1.2 release, it continues to influence thought patterns by bringing REST to the forefront. REST provides a set of principles for the design of network-based software. By presenting these patterns to a mainstream audience, Rails is having a profound impact on the future of software development.

The release also has numerous other improvements, including Unicode support, a new URL routing implementation, and better module loading.

This announcement came down from the top, by both Matz and Koichi. Matz, short for Yukihiro Matsumoto, is the creator of the Ruby language; Koichi is the developer of YARV, the “official” virtual machine for Ruby 2.0.

Making the situation more interesting is the development of two other interpreters, JRuby and RubyCLR. JRuby targets the Java VM, and is developed by Charles Oliver Nutter and Thomas Enebo, both of whom have recently been hired by Sun. RubyCLR, of course, targets the Common Language Runtime that powers .NET. It is developed by John Lam, who has been hired by Microsoft, not wanting to be left behind.

Chris Petrilli, provides a rundown of the current situation. And, while these VM efforts are admirable, Patrick Logan calls it like it is:

Seriously, Ruby is in dire need of a decent implementation. The JVM and the CLR are fine for what they are, old legacy. But Ruby needs its own *modern* implementation.

That leads me to Strongtalk. Strongtalk is a virtual machine for Smalltalk that adds on optional static type system, from which it derives its name. It was developed by a company named Animorphic, which was acquired by Sun, who put its engineers to work on the JVM.

Sun recently released the Strongtalk code under an open source, BSD-style license. Admittedly, the code has not been actively developed for about 10 years. Yet the research behind Strongtalk is state-of-the-art as far as dynamic, interpreted languages are concerned.

Having a Strongtalk-powered VM for Ruby would have a number of benefits. The most important benefit would be giving Ruby the advanced, high-performance VM that it desperately needs. Also not to be ignored is the the need a pure open source implementation, not mired by the questionable licenses that currently hinder both Java and the CLR. And, in my own idealistic programming world, it would unify Smalltalk and Ruby under a common runtime.

My Objective-C leanings lead me to use Ruby as a scripting language. Ruby has been propelled into the spotlight recently by Ruby on Rails, an incredible framework for developing web applications.

Objective-C and Ruby are both descendants of Smalltalk. All three languages are object-oriented, and have the notion of message passing as a central construct. Message passing is not found in more popular languages like C++ and Java, yet understanding it can give any developer an invaluable new perspective.

In an attempt to further my understanding of these concepts, I’ve recently been studying Smalltalk. While having been around for more than 30 years, the concepts behind the language are still considered state-of-the-art and its influence is broad. That influence extends all the way to the web, as I discovered in a recent entry by James Robertson.

Found in the comments is a link to an editorial by Dan Connolly, dated February 13, 1997. From the article:

HTTP was design as a distributed realization of the Objective C (originally Smalltalk) message passing infrastructure: the first few bytes of every HTTP message are a method name: GET or POST. Uniform Resource Locator is just the result of squeezing the term object reference through the IETF standardization process.

Recent projects have caused me to view the web as just such a distributed object system. However, I was not aware of the historical link to Objective-C and Smalltalk. Seen in that light, though, the message passing approach is remarkably consistent.

David Heinemeier Hansson, the creator of Ruby on Rails, is a true innovator in the web application frontier. His addition of Active Resource to edge Rails is the natural next step in this line of thinking. In his keynote address at RailsConf 2006, he gives a compelling presentation about the benefits of discovering a world of resources.

Message passing languages are efficient and productive for application development. Unfortunately, they have a minority stake of developer mindshare. Ruby and Rails are currently improving this situation. It may be wishful thinking, but I’d like to see these trends renew interest in Objective-C and Smalltalk as well.