Editing Ternary conditional operator (section)

===F#===

In [[F Sharp (programming language)|F#]] the built-in syntax for if-then-else is already an expression that always must return a value.

<syntaxhighlight lang="fsharp">
let num = if x = 10 then 42 else 24
</syntaxhighlight>

F# has a special case where you can omit the else branch if the return value is of type unit. This way you can do side-effects, without using an else branch.

<syntaxhighlight lang="fsharp">
if x = 10 then
    printfn "It is 10"
</syntaxhighlight>

But even in this case, the if expression would return unit. You don't need to write the else branch, because the compiler will assume the unit type on else.