Basic Syntax

Comments

# Single line comment

=begin
Multi-line
comment
=end

Statements and Expressions

Ruby statements don't require semicolons:

puts "Hello"
x = 5
y = x + 3

Case Sensitivity

Ruby is case-sensitive:

name = "Ruby"
Name = "Different"  # Different variable

Keywords

Ruby has reserved keywords that cannot be used as variable names:

# Some keywords: if, else, def, class, end, true, false, nil, etc.

Whitespace

Ruby uses whitespace for readability but doesn't enforce indentation like Python.

Line Continuation

Long lines can be continued with backslash:

result = 1 + 2 + 3 + \
         4 + 5 + 6

Everything is an Expression

In Ruby, almost everything returns a value:

x = if true then 1 else 0 end  # x = 1

y = case x
    when 1 then "one"
    when 2 then "two"
    else "other"
    end  # y = "one"

Method Calls

Parentheses are optional for method calls:

puts "Hello"     # Valid
puts("Hello")    # Also valid

String Literals

single = 'Single quotes'
double = "Double quotes with #{interpolation}"

Symbols

Symbols are immutable strings, often used as keys:

:key
:key_with_underscores

Constants

Constants start with capital letters:

PI = 3.14159
MY_CONSTANT = "value"

Parallel Assignment

a, b = 1, 2
x, y, z = [1, 2, 3]

Conditional Assignment

x ||= 5  # Assign only if x is nil or false

The end Keyword

Ruby uses end to close blocks, methods, classes, etc.:

def method
  if condition
    # code
  end
end

Code Blocks

# Do-end block
[1, 2, 3].each do |num|
  puts num
end

# Curly braces for single line
[1, 2, 3].each { |num| puts num }

Method Definition

def greet(name)
  "Hello, #{name}!"
end

Class Definition

class Person
  # class body
end

Modules

module MyModule
  # module body
end

File Structure

Ruby files typically have .rb extension.

Running Ruby Code

# Run a file
ruby myfile.rb

# Run inline code
ruby -e "puts 'Hello'"

# Start IRB
irb

Best Practices

• Use 2 spaces for indentation (not tabs)
• Keep lines under 80-100 characters
• Use meaningful variable names
• Follow Ruby naming conventions (snake_case for variables, CamelCase for classes)
• Use parentheses for method calls when passing multiple arguments
• Prefer double quotes for strings with interpolation

Ruby's syntax is designed to be readable and expressive, making it easy to write clean, maintainable code.