# CQ, a general call in International Morse code (ITU-R M.1677-1). No composer; the words are the arranger's. https://lab.glossema.dev/play/morse-cq/code
# It plays the notes of https://lab.glossema.dev/play/morse-cq, tone for tone.
# CQ calls all stations, DE means from, ROUTER is the station calling and K invites a reply.
# One tone, F5 at 698 Hz, keyed on and off at 20 words per minute: a unit of 60 ms.
# A dit sounds for one unit and a dah for three. The silence is one unit between the
# signals of a letter, three between letters and seven between words.
# The call goes out twice, with a pause between to listen for an answer.
{
  :local call "CQ CQ DE ROUTER ROUTER K"
  # Each letter of the call in Morse code: a dot for a dit, a dash for a dah.
  :local morse {"C"="-.-."; "D"="-.."; "E"="."; "K"="-.-"; "O"="---"; "Q"="--.-"; "R"=".-."; "T"="-"; "U"="..-"}
  :local pitch 698
  :local unit 60ms
  :local dit $unit
  :local dah ($unit * 3)
  :for pass from=1 to=2 do={
    # Before the second call, listen for a reply: 34 units after the word space.
    :if ($pass = 2) do={ :delay ($unit * 34) }
    :local start 0
    :while ($start < [:len $call]) do={
      # A word runs up to the next space; a space after the call ends the last one.
      :local end [:find ($call . " ") " " $start]
      :local word [:pick $call $start $end]
      :put $word
      :for i from=0 to=([:len $word] - 1) do={
        :local letter [:pick $word $i]
        :local code ($morse->$letter)
        :for j from=0 to=([:len $code] - 1) do={
          :if ([:pick $code $j] = ".") do={
            :beep frequency=$pitch length=$dit
            :delay $dit
          } else={
            :beep frequency=$pitch length=$dah
            :delay $dah
          }
          # One unit of silence after every signal,
          :delay $unit
        }
        # two more after a letter, to make three,
        :delay ($unit * 2)
      }
      # and four more after a word, to make seven.
      :delay ($unit * 4)
      :set start ($end + 1)
    }
  }
}