accept notes via --play or -p

src/flags.rs

@@ -13,6 +13,9 @@ pub struct Flags {
 
     #[arg(long, default_value = "super_small_font.sf2")]
     pub sound_font: String,
+
+    #[arg(short, long, default_value = "c 2e+")]
+    pub play: Option<String>,
 }
 
 impl Flags {

src/main.rs

@@ -13,7 +13,9 @@ fn main() {
         flags.sound_font,
         flags.sample_rate,
     ));
-    syn_seq.append("c 2e g");
+    if let Some(play) = flags.play {
+      syn_seq.append(play);
+    }
 
     play(syn_seq, flags.sample_rate, flags.bpm);
 }