
var total: int = 10
var completed: int = 7

// Single-arg call
let label_length = length("pending")

// Multi-arg call with mixed literal and expression arguments
let summary = concat("Completed ", completed, " of ", total, " tasks")

// Nested calls
let upper = toUpper(concat("hello ", "world"))

// Call result in a condition (auto-wraps since we can't prove it's boolean)
var items: array = []
if empty(items) {
  total = 0
}
