A logical control structure always starts with an if statement. As described previously, an if statement consists of the if keyword, a Boolean expression, and a then/end chunk. The then/end chunk is only executed when the Boolean condition evaluates to true. The following code sample demonstrates the basic use of an if statement:

print ("Enter your name")
name = io.read()

if #name <= 3 then
    print ("that's a short name, " .. name)
end