Ruby on Rails
What is Ruby?
Before we ride on Rails, let us recapitulate a few points of Ruby, which is the base of Rails.
Ruby is the successful combination of −
- Smalltalk's conceptual elegance,
- Python's ease of use and learning, and
- Perl's pragmatism.
Ruby is −
- A high-level programming language.
- Interpreted like Perl, Python, Tcl/TK.
- Object-oriented like Smalltalk, Eiffel, Ada, Java.
Why Ruby?
Ruby originated in Japan and now it is gaining popularity in US and Europe as well. The following factors contribute towards its popularity −
- Easy to learn
- Open source (very liberal license)
- Rich libraries
- Very easy to extend
- Truly object-oriented
- Less coding with fewer bugs
- Helpful community
Although we have many reasons to use Ruby, there are a few drawbacks as well that you may have to consider before implementing Ruby −
- Performance Issues− Although it rivals Perl and Python, it is still an interpreted language and we cannot compare it with high-level programming languages like C or C++.
- Threading model− Ruby does not use native threads. Ruby threads are simulated in the VM rather than running as native OS threads.
Sample Ruby Code
Here is a sample Ruby code to print "Hello Ruby"
# The Hello Class
class Hello
def initialize( name )
@name = name.capitalize
end
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def salute
puts "Hello #{@name}!"
end
end
# Create a new object
h = Hello.new("Ruby")
# Output "Hello Ruby!"
h.salute
Output − This will produce the following result −
Hello Ruby!
Embedded Ruby
Ruby provides a program called ERB (Embedded Ruby), written by Seki Masatoshi. ERB allows you to put Ruby codes inside an HTML file. ERB reads along, word for word, and then at a certain point, when it encounters a Ruby code embedded in the document, it starts executing the Ruby code.
You need to know only two things to prepare an ERB document −
- If you want some Ruby code executed, enclose it between <%and %>.
- If you want the result of the code execution to be printed out, as a part of the output, enclose the code between <%=and %>.
Here's an example. Save the code in erbdemo.rb file. Note that a Ruby file will have an extension .rb −
<% page_title = "Demonstration of ERB" %>
<% salutation = "Dear programmer," %>
<html>
<head>
<title><%= page_title %></title>
</head>
<body>
<p><%= salutation %></p>
<p>This is an example of how ERB fills out a template.</p>
</body>
</html>
Now, run the program using the command-line utility erb.
tp> erb erbdemo.rb
This will produce the following result −
