procedure main(A)
    sma := buildSMA(3)  # Use better name than "I".
    every write(sma(!A))
end

procedure buildSMA(P)
    local stream
    c := create {
        stream := []
        while n := (avg@&source)[1] do {
           put(stream, n)
           if *stream > P then pop(stream)
           every (avg := 0.0) +:= !stream
           avg := avg/*stream
           }
        }
    return (@c, c)
end