Ruby First

Ruby basics

Check version

ruby -v

irb

irb is conversationa dialogue style ruby script.

Start

irb

irb is irb command in bash

Test

p "Hello World!"

End

irb>> exit

Type exit

Value, Constants

a = 1
print a + 1

If missing initialization, value is nil
We can assign any types of value in variable.

Method

def add(a,b)  # def
   a + b
end
print add(1,2)  # Run

You can define 1 line using ;

def add(a,b); a + b; end

Class

class Homuhomu  # class
  def madoka    # method
  end
end
homu = Homuhomu.new
homu.madoka

Command Line Arguments

Ruby is an interpreter, command in bin(UNIX)

p "hello, Ruby"
p ARGV[0]   # Command Line Arguments
p ENV["PATH"] # Env PATH

Command Line Option

Comment

# is line comment

# Comment

==begin, ==end is block comment

=begin
   This is comment
=end

RDoc

RDoc is documentation style comment like JavaDoc
RDoc makes HTML style document.
Example

# = Homuhomu class
# Homuhomu is nickname of Akemi Homura
# 
class Homuhomu
  # == madoka Method for test
  # return value:: 1
  def madoka
     1
  end
end