Blocks are an important element of the Ruby programming language. You need to learn more about them to be a proficient Ruby programmer. Let’s delve into some more details on them.
THE BLOCKS IN RUBY DEVELOPMENT
In Ruby, handling blocks of code is very interesting. The methods you write can receive a block of code. From there, they do some very interesting things. Before we move on to this from receiving blocks in a method, I would like to give an example of a block:
5.times do |val|
puts val
end
The block in the example above starts with do and ends with end. Blocks can also be delimited with the curly brackets { }, although we do this usually when the block is a single line:
5.times { |val| puts val }
The most interesting thing about this syntax is that the methods of your objects can receive blocks. You would need to type the following:
def cool_method
yield
end
cool_method do
puts “Hello world”
end
Running the above script will result in a “Hello World” screen print. What happened is that when Ruby finds the keyword “yield”, it runs the block of code that was sent to the method. In this case the screen print of “Hello world”. What’s up? This has N cases in which it can be useful to you, infinity.
This was just an example, but there are many more interesting things. You can pass parameters to the block and you can validate that your method received a block.
METAPROGRAMMING
I know that many languages have this characteristic, Ruby is one of them, and it’s something very interesting. We can define meta programming as the ability of a language to modify a program at runtime, which means auto generating code. A much vaguer definition is to say that with a language that supports metaprogramming we can write code that generates code. For example:
[ “user” , “editor” , “admin” ].each_with_index do |user_level,index|
define_method(“is_#{user_level}?”) do
return true if user.permission_level == index
end
end
The snippet of previous code defines the methods is_user?, is_editor?, is_admin? without us writing them. The method defines_method does just that. It will define a method. That’s why we say it’s code that generates code.
This part of the language usually comes once you’ve learned many other things from Ruby, and of course, it’s not limited to the example I gave earlier, that’s just a part.
CONCLUSION
This is an article with 4 interesting features of a language that was designed to *make programmers happy, seriously. We wanted to give you a better overview of Ruby blocks, so that you can use them to get the most of your programming experience with Ruby.
The last feature I want to mention is that the best thing about Ruby is the community. It’s a big community, willing to help. There are a lot of very good Open Source projects (like Rails). There are a lot of forums with solutions to a lot of doubts and there are a lot of resources to learn how to use Ruby.
If you were interested in the language I invite you to follow the Ruby course of Easy Code or if you do not have problems with English. Follow the RubyMonk exercises where you can learn from the most basic to meta programming, advanced handling of blocks and things like that with exercises in the browser 🙂 You can also try Ruby in TryRuby where you learn the basics of the language in your browser.
Anyway, you can leave your suggestions, doubts and clarifications in the comments section, I hope you liked the post.