Since I am mostly experienced with java, I found some differences to be interesting.
- Ruby is object oriented, similar to Java.
- But everything is an object. Even primitive types such as integers are objects.
- Almost everything is a method call on some object. Even most operators are instance methods. You can do method calls on anything.
- 6.methods will return a list of methods that it will respond to.
- 1+2 means we pass the objects operator + and the number 2 to the send method of object 1. 1.send(:+, 2)
- Dynamically typed
- Even though objects have types, variable don't have types.
- Also, there are no declarations either
- That means, you just can use a variable without declaring first, and use it to store any type of object.
- Identifier Conventions
- Class names should UpperCamelCase similar to Java
- But methods and variable names should use snake_case unlike java's camelCase
- Ruby is pass-by-reference, since everything is an object. (whereas Java is pass-by-value.)
- Metaprogramming
- this basically means you can do some of the programming during the runtime, such as method definitions.
- Say there's an instance variable name. Instead of writing it's getter and setter, you can specify to create them during runtime using metaprogramming by: attr_accessor :name
- Iterators
- Iterations play a big role in Ruby.
- In Java, we usually run a loop with an index and do something with the object for the index in each iteration.
- In Ruby, iterating with an index is discouraged. Rather, we let objects manage their own traversal.
- my_array.each do |elt| {
} end - Duck Typing
- An object's current set of methods and properties determines the valid semantics, rather than its inheritance from a particular class or implementation of a specific interface.
- For example, you can call sort on arrays with different type of objects, strings, hashes, if they respond to the method somehow, without considering their types.
- Mix-ins
- This is used to achieve duck typing.
- In Ruby, there are things called Modules, A module is a collection of class & instance
methods that are not actually a class. Therefore you cannot instantiate it - But by including modules in your class you can resuse (mix) their methods
- class A < B ; include MyModule ; end . A.foo first search A, MyModule and finally B.
Ruby Installer is a nice packaging that makes it easy to install Ruby on Windows
