RosettaCodeData/Task/Morse-code/OCaml/morse-code.ocaml

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let codes = [
'a', ".-"; 'b', "-..."; 'c', "-.-.";
'd', "-.."; 'e', "."; 'f', "..-.";
'g', "--."; 'h', "...."; 'i', "..";
'j', ".---"; 'k', "-.-"; 'l', ".-..";
'm', "--"; 'n', "-."; 'o', "---";
'p', ".--."; 'q', "--.-"; 'r', ".-.";
's', "..."; 't', "-"; 'u', "..-";
'v', "...-"; 'w', ".--"; 'x', "-..-";
'y', "-.--"; 'z', "--.."; '0', "-----";
'1', ".----"; '2', "..---"; '3', "...--";
'4', "....-"; '5', "....."; '6', "-....";
'7', "--..."; '8', "---.."; '9', "----.";
]
let oc = open_out "/dev/dsp"
let bip u =
for i = 0 to pred u do
let j = sin(0.6 *. (float i)) in
let k = ((j +. 1.0) /. 2.0) *. 127.0 in
output_byte oc (truncate k)
done
let gap u =
for i = 0 to pred u do
output_byte oc 0
done
let morse =
let u = 1000 in (* length of one unit *)
let u2 = u * 2 in
let u3 = u * 3 in
let u6 = u * 6 in
String.iter (function
| ' ' -> gap u6
| 'a'..'z' | 'A'..'Z' | '0'..'9' as c ->
let s = List.assoc c codes in
String.iter (function
'.' -> bip u; gap u
| '-' -> bip u3; gap u
| _ -> assert false
) s; gap u2
| _ -> prerr_endline "unknown char")
let () = morse "rosettacode morse"