Function layers_to_range

cake-mobile/src/lib.rs:213–224

(layers: &[String])

// ---------------------------------------------------------------------------

fn layers_to_range(layers: &[String]) -> String {
    if layers.is_empty() {
        return "none".to_string();
    }
    let first_num = layers.first().and_then(|l| l.rsplit('.').next()).and_then(|n| n.parse::<usize>().ok());
    let last_num = layers.last().and_then(|l| l.rsplit('.').next()).and_then(|n| n.parse::<usize>().ok());
    match (first_num, last_num) {
        (Some(f), Some(l)) if f == l => format!("layer {}", f),
        (Some(f), Some(l)) => format!("layers {}–{} ({} total)", f, l, layers.len()),
        _ => format!("{} layer(s)", layers.len()),
    }
}

// ---------------------------------------------------------------------------
// Public entry point