Ruby programming and its basic conventions

5 Min. Read
Aug 18, 2019

Introduction: Ruby programming

Ruby is an object oriented programming language. Everything in ruby is taken as object. OO concepts basically includes two major things: Class and Objects. Class is nothing but an object which consists of variables or state and methods. State stores some value and methods perform action of some kind like print, delete etc. Objects or instance of class can be created by using new() method.

For e.g :

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class Animal
  @play
  def eat
    puts "Animal eats" #Animal eats
  end

  def move(a)
    puts "#{a} moves"
  end
end

animal1 = Animal.new  #Creates an instance of class Animal
animal1.eat           #Animal eats
animal1.move("Cat")   #Cat moves

Here, Animal is a class with instance variable @play and methods eat and move(a). Among them,eat method doesnot take any parameters whereas move(a) does. Here, the parameter is a. animal1 is an instance of class Animal so it can use all the variables and methods defined in class Animal. So, that was the basic introduction on Ruby. Let’s move to some of its conventions.

Ruby Conventions

Here I will be talking about some of the most important conventions in Ruby.

  1. Class names, module names, and constants must start with an uppercase letter. By convention they use capitalization to distinguish the start of words within the name. Eg: Animal, PurchaseOrder, StudentSubject etc.

  2. Local variables, method parameters, and method names should all start with a lowercase letter or with an underscore: order , _item , and xr2000 are all valid.

  3. Global variables start with $ like $name and class variables start with @@ like @@name.

  4. Use underscore to separate words in a multiword method or variable name. Eg: full_name, std_id, etc.

  5. Constants start with uppercase letter like Pi, Radius.

Reserved Words

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BEGIN       Code, enclosed in { and }, to run before the program runs.
END         Code, enclosed in { and }, to run when the program ends.
alias       Creates an alias for an existing method, operator, or global variable.
and         Logical operator; same as && except and has lower precedence.
begin       Begins a code block or group of statements; closes with end.
break       Terminates a while or until loop or a method inside a block.
\case       Compares an expression with a matching when clause; closes with end.
class       Defines a class; closes with end.
def         Defines a method; closes with end.
defined?    Determines if a variable, method, super method, or block exists.
do          Begins a block and executes code in that block; closes with end.
else        Executes if previous conditional, in if, elsif, unless, or when, is not true.
elsif       Executes if previous conditional, in if or elsif, is not true.
end         Ends a code block (group of statements) starting with begin, def, do, if, etc.
ensure      Always executes at block termination; use after last rescue.
false       Logical or Boolean false, instance of FalseClass. (See true.)
for         Begins a for loop; used with in.
if          Executes code block if true. Closes with end.
module      Defines a module; closes with end.
next        Jumps before a loop’s conditional.
nil         Empty, uninitialized variable, or invalid, but not the same as zero; object of NilClass.
not         Logical operator; same as !.
or          Logical operator;
redo        Jumps after a loop’s conditional.
rescue      Evaluates an expression after an exception is raised; used before ensure.
retry       Repeats a method call outside of rescue; jumps to top of block (begin) if inside rescue.
return      Returns a value from a method or block. May be omitted.
self        Current object (invoked by a method).
super       Calls method of the same name in the superclass. The superclass is the parent of this class.
then        A continuation for if, unless, and when. May be omitted.
true        Logical or Boolean true, instance of TrueClass.
undef       Makes a method in current class undefined.
unless      Executes code block if conditional statement is false.
until       Executes code block while conditional statement is false.
when        Starts a clause (one or more) under case.
while       Executes code while the conditional statement is true.
yield       Executes the block passed to the method.
_ FILE _    Name of current source file.
_ LINE _    Number of current line in the current source file.

Summary

Ruby Programming is an Object-Oriented Programming Language which has simple conventions and easy-to-use keywords. Following conventions,
it is easier to make software projects more readable and comprehensible. Besides, it helps to make project maintainable.

That’s all for today. See you next time.