Better handling of snake-ification of mixed input (#7)

src/traits.rs

@@ -57,15 +57,21 @@ pub trait SnakeCaseExt {
 impl SnakeCaseExt for String {
     fn to_snake_case(&self) -> String {
         let mut s = String::new();
+        let mut was_sep = false;
         if let Some(c) = self.chars().nth(0) {
+            was_sep = SEPARATORS.contains(c);
             s.push(c.to_lowercase().next().unwrap());
         }
         for c in self.chars().skip(1).into_iter() {
             if c.is_lowercase() {
-                s.push(c)
+                was_sep = false;
+                s.push(c);
             } else {
-                s.push('_');
-                if SEPARATORS.contains(c) {
+                if !was_sep {
+                    s.push('_');
+                }
+                was_sep = SEPARATORS.contains(c);
+                if was_sep {
                     continue;
                 } else {
                     s.push(c.to_lowercase().next().unwrap())

tests/integration.rs

@@ -33,6 +33,24 @@ fn it_works_to_snakecase() {
     assert!(snake!(a_bC1)());
 }
 
+#[test]
+fn it_works_to_snakecase_mixed() {
+    fn hello_world() -> bool {
+        true
+    }
+    fn hello_world_and_welcome() -> bool {
+        true
+    }
+    assert!(snake!(hello_world)());
+    assert!(snake!(hello_World)());
+    assert!(snake!(helloWorld)());
+    assert!(snake!(HelloWorld)());
+    assert!(snake!(hello_world_and_welcome)());
+    assert!(snake!(hello_world_andWelcome)());
+    assert!(snake!(hello_worldAndWelcome)());
+    assert!(snake!(hello_world_AndWelcome)());
+}
+
 #[test]
 fn it_works_to_pascalcase() {
     #[allow(non_snake_case)]