procedure Gen()	
    write("Gen: Starting up...")
    suspend 3

    write("Gen: More computing...")
    suspend 7

    write("Gen: Out of gas...")
    fail  # not really needed
end

procedure main()
    while writes("Value? ") & n := integer(read()) do {
        if n = Gen() then
            write("Found ", n)
        else
            write(n, " not found")
        }
end