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Introduction
Every product has a name and identifies itself with the same. The name of the product is its identity and value. Similarly, identifiers in ruby are nothing but just simply a name. Name to a variable, method, classes, etc., are all identifiers in ruby. But sometimes, a product cannot be called with certain words as these trademarks may be owned by some organisations or individuals, so no one else could use it.
In the same way, keywords in ruby are some reserved words that are reserved for doing some specific tasks. Users cannot have a keyword as an identifier; ruby trademarks it. The way Xbox trademark is owned by Microsoft so that no other manufacturer could name their product Xbox. Similarly, no identifiers could be named as a keyword.
In the below section, we will discuss keywords in ruby in detail but before that, let's get to know about ruby and lexical structure in ruby in brief.
Ruby
Ruby
Ruby is an open-source dynamic language with natural and easy-to-read/write syntax. Ruby is a language of careful balance and is a perfect blend of five different languages (Perl, Smalltalk, Eiffel, Ada, and Lisp). Often, its creator Yukihiro "Matz" Matsumoto considers ruby as a human being in the sense that the way human beings are simple from the outside but complex from the inside. Like human bodies, ruby is simple in appearance but complex on the inside. So I think you get to know in brief about ruby, so let us have a brief idea about lexical structure in Ruby before we go into details to understand keywords in ruby.
Lexical Structure
Like Human Languages, computer languages also follow a lexical structure. A source code of the ruby program consists of tokens. While parsing any program, the ruby-interpreter parses the program as a sequence of these tokens. Tokens in ruby include literal, punctuation, comments, identifiers, and keywords. This article introduces you to one type of token, i.e., Keywords in ruby. Tokens also include essential information about the characters that comprise the tokens and the whitespace that separates the tokens.
Identifiers in Ruby
An identifier in ruby is simply a name. Ruby uses these identifiers to name variables, classes, methods, etc. Identifiers in ruby consist of letters, numbers, and underscore characters, but they do not begin with a number. Also, Identifiers in ruby do not include whitespace or nonprinting characters or punctuation characters except as described here.
Let us look into some sample identifiers.
i
X2
old_value # multiword identifiers in ruby that are not constant
_internal # Identifiers may begin with underscores
PI # Constant
NEW_VALUE # multiword identifiers in ruby for constant
Keywords in Ruby
As we have already stated in the introduction, Keywords in ruby are nothing but reserved words used for some specific internal process or represent some predefined actions. No variable Object or constant could be named a keyword. Users cannot have a keyword as an identifier. Doing this will give a compile-time error in ruby. E.g. we will get a compile-time error by running the below code since it uses the keyword "if" as a prohibited variable.
Code:-
# Program to illustrate Keywords in ruby
# !/usr/bin/ruby
# "if" is a keyword in ruby, so the user can't use it as a variable
if = 20
# Here, 'if' and 'end' are keywords in ruby
# if the condition is used to check whether user age is enough for voting
if if >= 18
puts "User eligible to vote."
end
You can also try this code with Online Ruby Compiler
Now we will see all 41 keywords in ruby and what are there internal functions they perform.
KEYWORDS IN RUBY
DESCRIPTION
BEGIN
Code inside BEGIN will run before any other code written in the current file.
END
Code inside END will run after any other code written in the current file
alias
It helps to create an alias between two methods
and
It has lower precedence than && and is for short-circuit boolean
begin
It helps us to start an exception handling block
break
The break helps to leave a block early
case
It helps to start a case expression
class
Helps user to create or opens a class in ruby
def
def keyword in ruby helps us to define a function
defined?
Defined? It describes its argument by returning a string
do
It helps to start a block of code
else
Else is the unhandled condition in if and unless expression
elsif
Elsif helps the user to give alternate conditions to if expression
end
methods, modules, classes etc, use end. It indicates the end of a syntax block
false
False here means boolean false
ensure
ensure is a block of code that will always run when an exception is raised
for
To help us to create a loop for iteration
if
Used as an expression for if or modifiers if
in
It helps to separate iterable Objects and iterable variables in a for loop
module
Helps us in creating or opening module
next
Lets the user skips the rest of the code in the block
nil
Nil represents false value indicating "no value" or "unknown."
not
It inverts the boolean expression but has less precedence than "!"
or
It represents boolean or with less precedence than "||"
redo
Redo helps to restart execution in the present block
rescue
It helps to start an exception section of code in a beginning block
retry
It helps us to retries an exception block
return
To exit from a method
self
Helps in calling Object of current method attached to
super
It helps in calling the current method in a superclass
then
In control structure, It represents the end of the conditional block
true
true here is just a simple boolean true expression
undef
It helps in preventing module or class from responding to the method call
unless
It helps in creating unless and modifiers unless expressions
until
Help us to create an iterative loop until a condition is met
when
it helps by representing a condition in a case expression
while
Help us to create an iterative loop while a condition is true
yield
yield Helps to start execution of block send to the current method
_ENCODING_
It represents script encoding of the current file
_LINE_
It represents the line number of keywords in the current file
_FILE_
It represents the path to the current file.
Frequently Asked Questions
What is Ruby?
Ruby is an open-source dynamic language with natural and easy-to-read/write syntax. Ruby is a language of careful balance and is a perfect blend of five different languages.
Ruby is said to be a combination of which five languages?
Ruby, an open-source dynamic language, is a perfect blend of five different languages (Perl, Smalltalk, Eiffel, Ada, and Lisp).
What are Keywords in ruby?
Keywords in ruby are nothing but reserved words used for some specific internal process or represent some predefined actions.No variable, Object, or constant could be named a keyword.
Is Ruby Case Sensitive?
Ruby is a case-sensitive language, which means lowercase identifiers in ruby are different from uppercase identifiers. E.g. Like_This is entirely different from LIKE_THIS. Similarly, Start is different from START.
What does the keyword _FILE_ signify?
Keyword _FILE_ helps us represent the current file's path.
Conclusion
In this article, we have studied in detail the Keywords in Ruby and briefly explored all the Keywords in Ruby.
We expect that this article must have helped you enhance your knowledge on the topic of Ruby. Please upvote our blogs if you find them engaging and helpful!
We wish you all the best for your future adventures and Happy Coding.
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