Conditional Execution (if, then, else, end)

Conditional statements execute different code paths based on boolean expression evaluation. The if statement supports multiple else if branches for complex decision trees and an optional final else branch for default behavior.

IfStmt           = "if" Expression "then" { Statement }
                   { "else" "if" Expression "then" { Statement } }
                   [ "else" { Statement } ] "end" ;

Each condition is evaluated in sequence until one evaluates to true, at which point the corresponding statement block executes and control transfers to the statement following the end keyword. If no conditions evaluate to true, the optional else block executes.

Valid Syntax:

if condition then
    DoSomething()
end

if score >= 90 then
    grade = "A"
else if score >= 80 then
    grade = "B"
else
    grade = "F"
end

if condition then DoSomething() end  # Statements can be on the same line

Notes

• if statements must be terminated with end
• The then keyword is required after each condition
• else if is written as two separate keywords