Ruby is a language of careful balance. Its creator, Yukihiro “matz” Matsumoto, blended parts of his favorite languages (Perl, Smalltalk, Eiffel, Ada, and Lisp) to form a new language that balanced functional programming with imperative programming.

He has often said that he is “trying to make Ruby natural, not simple,” in a way that mirrors life.

Building on this, he adds:

Ruby is simple in appearance, but is very complex inside, just like our human body.

Seeing Everything as an Object

Initially, Matz looked at other languages to find an ideal syntax. Recalling his search, he said, “I wanted a scripting language that was more powerful than Perl, and more object-oriented than Python³.”

In Ruby, everything is an object. Every bit of information and code can be given their own properties and actions. Object-oriented programming calls properties by the name instance variables and actions are known as methods. Ruby’s pure object-oriented approach is most commonly demonstrated by a bit of code which applies an action to a number.

5.times { print "We *love* Ruby -- it's outrageous!" }

In many languages, numbers and other primitive types are not objects. Ruby follows the influence of the Smalltalk language by giving methods and instance variables to all of its types. This eases one’s use of Ruby, since rules applying to objects apply to all of Ruby.

Ruby’s Flexibility

Ruby is seen as a flexible language, since it allows its users to freely alter its parts. Essential parts of Ruby can be removed or redefined, at will. Existing parts can be added upon. Ruby tries not to restrict the coder.

For example, addition is performed with the plus (+) operator. But, if you’d rather use the readable word plus, you could add such a method to Ruby’s builtin Numeric class.

class Numeric
  def plus(x)
    self.+(x)

  end
end

y = 5.plus 6

# y is now equal to 11

Ruby’s operators are syntactic sugar for methods. You can redefine them as well.

Blocks, a Truly Expressive Feature

Ruby’s block are also seen as a source of great flexibility. A programmer can attach a closure to any method, describing how that method should act. The closure is called a block and has become one of the most popular features for newcomers to Ruby from other imperative languages like PHP or Visual Basic.

Blocks are inspired by functional languages. Matz said, “in Ruby closures, I wanted to respect the Lisp culture⁴.”

search_engines = 



  %w[Google Yahoo MSN].map do |engine|



    "http://www." + engine.downcase + ".com"



  end

In the above code, the block is described inside the do ... end construct. The map method applies the block to the provided list of words. Many other methods in Ruby leave a hole open for a coder to write their own block to fill in the details of what that method should do.

Ruby and the Mixin

Unlike many object-oriented languages, Ruby features single inheritance only, on purpose. But Ruby knows the concept of modules (called Categories in Objective-C). Modules are collections of methods.

Classes can mixin a module and receive all its methods for free. For example, any class which implements the each method can mixin the Enumerable module, which adds a pile of methods that use each for looping.

class MyArray

  include Enumerable

end

Generally, Rubyists see this as a much clearer way than multiple inheritance, which is complex and can be too restrictive.