Aggregation with agg()

034_aggregation.cell

// ============================================================================
// 034 — Aggregation with agg()
// ============================================================================
// agg() groups by a field and computes aggregates (sum, avg, count, etc).
//
// Run:   soma run 034_aggregation.cell run
// Expect:
//   Department summary:
//     Eng: 2 people, total salary 210k, avg 105k
//     Sales: 2 people, total salary 170k, avg 85k
//     Design: 1 people, total salary 95k, avg 95k

cell Aggregation {

    on run() {
        let employees = list(
            map("dept", "Eng", "name", "Alice", "salary", 120),
            map("dept", "Eng", "name", "Bob", "salary", 90),
            map("dept", "Sales", "name", "Carol", "salary", 85),
            map("dept", "Sales", "name", "Dave", "salary", 85),
            map("dept", "Design", "name", "Eve", "salary", 95)
        )

        // agg(list, group_by_field, "col:func", ...)
        // Available functions: sum, avg, count, min, max
        let summary = employees
            |> agg("dept", "salary:sum", "salary:avg")

        print("Department summary:")
        for row in summary {
            print("  {row.dept}: {row.count} people, total salary {row.salary_sum}k, avg {row.salary_avg}k")
        }

        return "done"
    }
}