Conditional Expressions

Use the ?: operator only for simple conditional expressions that fit onto a single line. If the conditional expression requires more than one line, or if you think that readability is important, use if then else endif instead.

Here is an example of using the ?: operator:

let maxStr = (x > y) ? "x is greater" : "y is greater"

Here is an example of using if then else endif, spanning several lines:

let maxStr =
    if (x > y) then
        "x is greater"
    else
        "y is greater"
    endif

Place the keywords if, else, and endif at the same indentation level. This applies to elsif clauses as well, as in the following example:

if a matches binaryOperator as b then {
    lhs = b.lhsExpression;
    rhs = b.rhsExpression
} elsif a matches unaryOperator as b then {
    lhs = b.operandExpression;
    rhs = null
} else {
    lhs = a;
    rhs = null
} endif

If the logic of the conditions is hard to follow, it might be better to nest if-expressions, as the next example shows:

if e.type matches intType { .isSigned == true } then
    let interval = getIntegerInterval(e) in
        if interval.lower matches NonNull as lower && lower gt;= 0 then
            `NEVER`
        else
            if interval.upper matches NonNull as upper && upper < 0 then
                `SURE`
            else
                `UNKNOWN`
            endif
        endif
else
    `NEVER`
endif