Lists

main (print)

main()
    xs = [int: 10, 20, 30]
    first = xs[0]
    n = len(xs)
    # Appending spreads the old list into the new one and consumes it.
    xs = [*xs, 40]
    # Replacing an element does the same.
    xs = [*xs, 1 = 25]
    # A slice is a view of a range; it copies nothing.
    tail = xs[1:len(xs)]
    m = len(tail)
    print.line("{first} {n} {m} {xs[1]} {xs[3]}")

10 3 3 25 40