Fix roundtrip in f32_hz_then_khz_with_note_names

src/formatters.rs

@@ -180,17 +180,18 @@ pub fn s2v_f32_hz_then_khz() -> Arc<dyn Fn(&str) -> Option<f32> + Send + Sync> {
     Arc::new(move |string| {
         let string = string.trim();
 
-        // If the user inputs a note representation, then we'll use that
+        // The input can contain a frequency in Hz or kHz, a note name, a note name and cents, or
-        if let Some(midi_note_number) = note_formatter(string) {
+        // one of those two combined with a frequency. In the last case we'll ignore the frequency.
-            return Some(util::f32_midi_note_to_freq(midi_note_number as f32));
+        // If the string cannot be parsed as a note name, we'll try parsing it as a frequency
-        }
+        // instead. This is needed for the formatting roundtrip to work correctly. The input will
+        // consists of 1 to three segments, so we'll try to unpack them like this so we can pattern
+        // match on them
+        let mut segments = string.split(',');
+        let segments = (segments.next(), segments.next(), segments.next());
 
-        // This can also contain semitones. If we cannot parse this as a note name, we'll try
+        if let (_, Some(midi_note_number_str), Some(cents_str))
-        // parsing it as a frequency instead. We'll also `XXX Hz, C3` where `XXX Hz` does not match
+        | (Some(midi_note_number_str), Some(cents_str), None) = segments
-        // C3 since the user may just edit that of the text input box while leaving the note name
+        {
-        // untouched.
-        let string = if let Some((midi_note_number_str, cents_str)) = string.split_once(',') {
-            // If it contains a comma we'll also try parsing cents
             let cents_str = cents_str
                 .trim_start_matches([' ', '+'])
                 .trim_end_matches([' ', 'C', 'c', 'E', 'e', 'N', 'n', 'T', 't', 'S', 's', '.']);
@@ -203,22 +204,23 @@ pub fn s2v_f32_hz_then_khz() -> Arc<dyn Fn(&str) -> Option<f32> + Send + Sync> {
                 let cents_multiplier = 2.0f32.powf(cents as f32 / 100.0 / 12.0);
                 return Some(plain_note_freq * cents_multiplier);
             }
+        }
 
-            // NOTE: As mentioned above, if the input contained a `,` we'll try parsing the part
+        if let (_, Some(midi_note_number_str), _) | (Some(midi_note_number_str), None, None) =
-            //       before the comma as a frequency string if we could not parse the right hand
+            segments
-            //       side has a note string. This can happen if the user edits the output of
+        {
-            //       `v2s_f32_hz_then_khz_with_note_name()`.
+            if let Some(midi_note_number) = note_formatter(midi_note_number_str) {
-            midi_note_number_str
+                return Some(util::f32_midi_note_to_freq(midi_note_number as f32));
-        } else {
+            }
-            string
+        }
-        };
 
         // Otherwise we'll accept values in either Hz (with or without unit) or kHz
-        let cleaned_string = string
+        let frequency_segment = segments.0?;
+        let cleaned_string = frequency_segment
             .trim_end_matches([' ', 'k', 'K', 'h', 'H', 'z', 'Z'])
             .parse()
             .ok();
-        match string.get(string.len().saturating_sub(3)..) {
+        match frequency_segment.get(frequency_segment.len().saturating_sub(3)..) {
             Some(unit) if unit.eq_ignore_ascii_case("khz") => cleaned_string.map(|x| x * 1000.0),
             // Even if there's no unit at all, just assume the input is in Hertz
             _ => cleaned_string,