impl parse tone str

src/tone.rs

@@ -0,0 +1,71 @@
+#[derive(Debug)]
+pub struct Tone(i32);
+
+// new parses [a-g][+-]?[1-5]? to tone, sharp or flat, down 2 octave..up 1 octave
+pub fn new<S: ToString>(s: S) -> Tone {
+   Tone::new(s.to_string())
+}
+
+impl Tone {
+   fn new(s: String) -> Tone {
+      let re = regex::Regex::new(r"^((?<letter>^[a-g])(?<sharpness>[+-]?)(?<octave>[1-5]?)|(?<numeric>[0-9]+))$").unwrap();
+      let captures = re.captures(s.as_ref()).unwrap();
+      Tone (match captures.name("numeric") {
+         Some(number) => number.as_str().parse::<i32>().unwrap(),
+         None => {
+            let mut result = match captures.name("letter").unwrap().as_str() {
+               "a" => 57,
+               "b" => 59,
+               "c" => 60,
+               "d" => 62,
+               "e" => 64,
+               "f" => 65,
+               _ => 67,
+            } as i32;
+
+            result += match captures.name("sharpness") {
+               Some(sharpness) => match sharpness.as_str() {
+                  "+" => 1,
+                  "-" => -1,
+                  _ => 0,
+               },
+               None => 0,
+            } as i32;
+
+            result += match captures.name("octave") {
+               Some(octave) => match octave.as_str() {
+                  "" => 0,
+                  _ => (octave.as_str().parse::<i32>().unwrap() - 3) * 12,
+               },
+               None => 0,
+            } as i32;
+
+            result
+         },
+      })
+   }
+
+   pub fn i32(&self) -> i32 {
+      self.0
+   }
+}
+
+#[cfg(test)]
+mod test {
+   #[test]
+   fn test_tone_new() {
+      assert_eq!(super::new("60").i32(), 60);
+
+      assert_eq!(super::new("c").i32(), 60);
+      assert_eq!(super::new("e").i32(), 64);
+      assert_eq!(super::new("g").i32(), 67);
+
+      assert_eq!(super::new("c+").i32(), 60+1);
+      assert_eq!(super::new("c-").i32(), 60-1);
+
+      assert_eq!(super::new("c3").i32(), 60);
+      assert_eq!(super::new("c4").i32(), 60+12);
+
+      assert_eq!(super::new("c+4").i32(), 60+12+1);
+   }
+}