Lua Keywords: A Beginner’s Guide to Understanding Lua Reserved Words

Lua keywords are special words that have specific meanings in the Lua programming language. They are reserved by the language and cannot be used for other purposes, like naming variables or functions. Understanding these keywords is essential for writing correct and efficient Lua code.​

List of Lua

Lua has a set of 21 reserved keywords:​

• And
• Break
• Do
• Else
• Elseif
• End
• False
• For
• Function
• If
• In
• Local
• Nil
• Not
• Or
• Repeat
• Return
• Then
• True
• Until
• while​

These keywords are integral to the structure and control flow of Lua programs.​

Understanding this keyword

Let’s explore some of these to understand their roles in Lua programming.

Control Flow Keywords

• if, then, else, elseif, end: Used for conditional statements.

if condition then
— code to execute if condition is true
elseif another_condition then
— code to execute if another_condition is true
else
— code to execute if none of the above conditions are true
end

• for, while, repeat, until: Used for loops
• for i = 1, 10 do
  print(i)
  end
• while condition do
  — code to execute while condition is true
  end
• repeat
  — code to execute
  until condition

Logical Operators

• and, or, not: Used for logical operations.
• if condition1 and condition2 then
  — code to execute if both conditions are true
  end
• if condition1 or condition2 then
  — code to execute if at least one condition is true
  end
• if not condition then
  — code to execute if condition is false
  end

Other Keywords

• function: Used to define functions
• function greet()
  print(“Hello, World!”)
  end
• return: Used to return values from functions.
• function add(a, b)
  return a + b
  end
• local: Used to define local variables.
• local x = 10
• nil: Represents a null value
• local x = nil
• true, false: Boolean values.
• local isAvailable = true

Lua Keywords: A Beginner’s Guide to Understanding Lua Reserved Words

FAQs

Q1: Can I use these keywords as variable names?

No, these keywords are reserved and cannot be used as variable names.​

Q2: Are these keywords case-sensitive?

Yes, Lua is case-sensitive. For example, if is a keyword, but If or IF are not.​

Q3: How many keywords does Lua have?

Lua has 21 reserved keywords.​

Q4: What happens if I try to use a keyword as a variable name?

It will throw a syntax error if you try to use a keyword as a variable name.​

Conclusion

Understanding this keywords is fundamental to writing effective Lua code. These reserved words define the structure and control flow of your programs. By familiarizing yourself with them, you can write clearer and more efficient code.​

For more information on this keywords, you can refer to the Lua 5.1 Reference Manual or the Lua 5.4 Reference Manual.