note_to_freq.ck

class Note{
    int octave;
    string str;
    float volume;
    float length;
    fun void make( int oct, string s, float vol, float len) { 
        oct => octave; 
        s => str;
        vol => volume;
        len => length;
    }
}

fun int to_note(Note n){
    // check if within supported range
    if (n.str == "off") return -1;
    if (n.octave < 0 || n.octave > 10) return -1;

    string notes_list[];
    ["C","C#","D","D#","E","F","F#","G","G#","A","A#","B"] @=> notes_list;
    
    // note must be in this list, else return -1 at the end
    for (0 => int i; i < notes_list.cap(); i++){
        if (n.str == notes_list[i]){
            return (i + n.octave * 12);
        }
    }
    return -1; 
}

fun float int_to_freq(int n){
    return 440.0 * Math.pow(2, (n-69)/12);
}

Note n1;
"C#" => n1.str;
4 => n1.octave;

to_note(n1) => int midi_int;
<<< midi_int >>>;

int_to_freq(midi_int) => float out_freq;
<<< out_freq >>>;