Conditions

An if condition must have type bool; Nenu has no truthy conversion.
Use else if for ordered alternatives and else for the final fallback path.
Keep each branch responsible for one decision and move reusable calculations outside it.

Basic Syntax

code

1if expense.amount > 0 {2  valid = true3}45if expense.status == ExpenseStatus.Settled {6  label = "Settled"7} else {8  label = "Open"9}

The expression between if and { must resolve to bool. Parentheses around the condition are unnecessary. The braces are required even for one statement.

Ordered Alternatives

code

1if balance > 0 {2  label = "Is owed money"3} else if balance < 0 {4  label = "Owes money"5} else {6  label = "Even"7}

Branches are checked from top to bottom. The first true condition runs, and later alternatives are skipped. Put the narrowest or highest-priority case first.

Combining Conditions

code

1can_settle = amount > 0 and balance < 02needs_attention = amount <= 0 or title == ""34if can_settle and expense.status != ExpenseStatus.Settled {5  ready = true6}

Operator	Meaning	Operand type
`and`	Both conditions are true.	`bool`
`or`	At least one condition is true.	`bool`
`!`	Invert one condition.	`bool`
Comparison operators	Compare compatible values.	Depends on the compared type.

Ternary Expressions

code

1string label = expense.status == ExpenseStatus.Settled : "Settled" | "Open"2number signed_amount = balance < 0 : -balance | balance

Use condition : then_value | else_value when one boolean decision produces one value. The condition must be bool, and both result expressions must have compatible types. Nenu permits at most two nested ternary levels; use an if statement or helper function for deeper branching.

Room Expense Example

code

1if request.amount <= 0 {2  throw BadRequest("Amount must be greater than zero")3}45if request.title == "" {6  throw BadRequest("Title is required")7}89Expense expense = Expense {10  room_id: room.id11  payer12  title: request.title13  amount: request.amount14  note: ?15  receipt: ?16  status: ExpenseStatus.Open17}1819save(expense)20return Response { expense }

The early branches stop invalid requests before construction or persistence. The successful path stays unindented and easy to read.

Common Mistakes

Wrong	Correct	Reason
`if amount { ... }`	`if amount > 0 { ... }`	Numbers are not truthy.
`if note { ... }`	`with note { ... }`	Optionals require presence proof.
`elif`	`else if`	Nenu uses two keywords.
`if condition then`	`if condition { ... }`	There is no then keyword.
`condition ? a : b`	`condition : a \| b`	Nenu uses colon and pipe for a ternary expression.

Continue Learning

Loops Use conditions inside typed collection iteration.Presence Guards Choose paths based on whether an optional value exists.