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By Root 621 0

work hard to do reflection, and it makes you use unnatural techniques like byte code enhancement, code generation, and dynamic proxies. On the other hand, Ruby handles metaprogramming with ease. For example, the Rails framework, Active Record, defines belongs_to and has_many methods describing database relationships. Each method adds additional Ruby behavior and attributes to the decorated class. At the most basic level, the Ruby language itself uses metaprogramming to describe attributes. attr_accessor :name is shorthand for this:

def name=(value)

@name=value

end

def name

@name

end

You get a syntax with less repetition, and the language developers did not have to work very hard to give it to you. Of course, Java also does metaprogramming. It just doesn't do it very well.

Ruby interests me for several other reasons, too. Ruby is a chameleon with enough theoretical headroom to grow beyond Rails with ease, and a simple enough syntax to excite beginners and educators. Ruby will let you do functional programming, or play with continuations. You can write full web-based applications, or slip into scripting for rudimentary text processing. Ruby gives you a language that's theoretically pure, and practical.

Ruby might not have the extensive libraries of Java, but it's closing the gap rapidly. It's also worth mentioning that Ruby is doing so with a fraction of the developers, because Ruby is just so productive. As Java moves more and more toward metaprogramming, this productivity gap will increase.

Against

The biggest strike against Ruby right now is the lack of a strong project that lets Ruby run on the JVM. The JRuby project's vision is greater than a simple port to the JVM. So far, the project has had several stops and starts. It's not far enough along to, for example, run Ruby on Rails. Most in the Ruby community don't see the political importance of a language that runs on the JVM, but interest and participation in the project may be picking up. JRuby seeks to let you use Java classes using Ruby idioms. For example, you'll be able to use Ruby code blocks with Java collections. If Microsoft is able to woo the Ruby founders over to .NET's CLR, or if the JRuby project starts picking up momentum, you'll see one of the biggest strikes against Ruby go away. Still, the lack of a credible version that runs on a widely deployed virtual machine, be it Microsoft or Java, is a major strike against Ruby. To be fair, the JRuby project in the months just before publication has made incredible strides. It now passes over 90% of the test cases for the basic Ruby platform. When it reaches Version 1.0 and can run Ruby on Rails suitably, Ruby will become a much stronger contender. Any language that embraces and extends Java will be in a much stronger political position.

Also, Ruby does not have the excellent commercial backing of some of the other alternatives. For example, Google uses Python extensively. Though Ruby is gaining traction in Japan, and also at places like Amazon.com, it's still a relative unknown. You can't yet hire Ruby programmers in numbers, and your training options are limited. If the Rails project hits a critical mass, that will change in a hurry.

A Word About Lisp

Lisp addicts might wonder why their beloved language is not higher on my list. In fact, Lisp has many of the characteristic of Ruby, with superior metaprogramming, a more extensive language, a good functional model, readable macros, and a clean and consistent interface. Lisp has never had the all-important marketing visionary, a catalyst, or the approachability of Ruby. It's also got history and a reputation to overcome. Ruby also has some other telling advantages: better regular expressions, parallel assignments (x, y = y+1, x+1), effective modules, better encapsulation (like private or protected methods), and standardized threads. True, many of these things have been done in Lisp, but Ruby provides a clean, standard solution in the language.

Overall

Major factors, including a comparative lack of libraries and the absence of a