Create a trait to avoid an unnecessary Result

src/words.rs

@@ -13,25 +13,39 @@ lazy_static! {
 
 pub(crate) fn list(path: Option<impl AsRef<Path>>) -> Result<Vec<String>> {
     match path {
-        Some(path) => words_from_file(path),
-        None => words_from_fixture(),
+        Some(path) => WordsFromFile { path }.words(),
+        None => WordsFromFixture {}.words(),
     }
 }
 
-fn words_from_fixture() -> Result<Vec<String>> {
-    let bytes = include_bytes!("fixtures/words");
-    Ok(String::from_utf8_lossy(bytes)
-        .split('\n')
-        .filter(|w| RE.is_match(w))
-        .map(|l| l.to_owned())
-        .collect())
+trait Words {
+    fn words(&self) -> Result<Vec<String>>;
 }
 
-fn words_from_file(path: impl AsRef<Path>) -> Result<Vec<String>> {
-    let file = File::open(path)?;
-    Ok(BufReader::new(file)
-        .lines()
-        .map_while(|l| l.ok())
-        .filter(|w| RE.is_match(w))
-        .collect())
+struct WordsFromFixture;
+
+impl Words for WordsFromFixture {
+    fn words(&self) -> Result<Vec<String>> {
+        let bytes = include_bytes!("fixtures/words");
+        Ok(String::from_utf8_lossy(bytes)
+            .split('\n')
+            .filter(|w| RE.is_match(w))
+            .map(std::borrow::ToOwned::to_owned)
+            .collect())
+    }
+}
+
+struct WordsFromFile<P: AsRef<Path>> {
+    path: P,
+}
+
+impl<P: AsRef<Path>> Words for WordsFromFile<P> {
+    fn words(&self) -> Result<Vec<String>> {
+        let file = File::open(&self.path)?;
+        Ok(BufReader::new(file)
+            .lines()
+            .map_while(std::result::Result::ok)
+            .filter(|w| RE.is_match(w))
+            .collect())
+    }
 }