Conditional Statements

if / else

pub fn max(a: i32, b: i32) -> i32 {
    if a > b {
        return a;
    } else {
        return b;
    }
}

if / else if / else

pub fn classify(x: i32) -> i32 {
    if x > 0 {
        return 1;
    } else if x < 0 {
        return -1;
    } else {
        return 0;
    }
}

Important Differences

if is a statement, not an expression. You cannot write let x: i32 = if condition { 1 } else { 2 };. Use a mutable variable instead:

pub fn example(condition: bool) -> i32 {
    let mut result: i32 = 0;
    if condition {
        result = 1;
    } else {
        result = 2;
    }
    return result;
}

The condition must be bool. Inference does not coerce integers to booleans. Write if x != 0 { ... } instead of if x { ... }.

Curly braces are required, even for single-statement branches.