Conditional evaluation

Conditional evaluation means that pieces of code are evaluated, depending on whether a Boolean expression is either true or false. The familiar if...elseif...else...end syntax is used here, which is as follows:

# code in Chapter 4\conditional.jl 
var = 7 
if var > 10 
    println("var has value $var and is bigger than 10.") 
elseif var < 10 
    println("var has value $var and is smaller than 10.") 
else 
    println("var has value $var and is 10.") 
end 
# => prints "var has value 7 and is smaller than 10."

The elseif (of which there can be more than one) or else branches are optional. The condition in the first branch is evaluated, only the code in that branch is executed when the condition is true, and so on; so only one branch ever gets evaluated. No parentheses around condition(s) are needed, but...