error handling for dialogues

src/dialogue.rs

@@ -1,5 +1,7 @@
 use crate::optional_data_line;
 
+use std::fmt;
+
 #[derive(Clone, Debug, Eq, PartialEq)]
 pub struct Dialogue {
     pub id: String,
@@ -7,10 +9,9 @@ pub struct Dialogue {
     pub name: Option<String>,
 }
 
-impl From<String> for Dialogue {
-    #[inline]
-    fn from(string: String) -> Dialogue {
-        let mut lines: Vec<&str> = string.lines().collect();
+impl Dialogue {
+    pub fn from_str(str: &str) -> Result<Dialogue, crate::Error> {
+        let mut lines: Vec<&str> = str.lines().collect();
         let id = lines[0].replace("DLG ", "");
 
         let name = if lines.last().unwrap().starts_with("NAME ") {
@@ -21,13 +22,14 @@ impl From<String> for Dialogue {
 
         let contents = lines[1..].join("\n");
 
-        Dialogue { id, contents, name }
+        Ok(Dialogue { id, contents, name })
     }
 }
 
-impl ToString for Dialogue {
-    fn to_string(&self) -> String {
-        format!(
+impl fmt::Display for Dialogue {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(
+            f,
             "DLG {}\n{}{}",
             self.id,
             self.contents,
@@ -41,10 +43,10 @@ mod test {
     use crate::Dialogue;
 
     #[test]
-    fn dialogue_from_string() {
-        let output = Dialogue::from(
-            "DLG h\nhello\nNAME not a dialogue name\nNAME a dialogue name".to_string()
-        );
+    fn dialogue_from_str() {
+        let output = Dialogue::from_str(
+            "DLG h\nhello\nNAME not a dialogue name\nNAME a dialogue name"
+        ).unwrap();
 
         let expected = Dialogue {
             id: "h".to_string(),
@@ -63,7 +65,7 @@ mod test {
             name: Some("a dialogue name".to_string())
         }.to_string();
 
-        let expected = "DLG y\nThis is a bit of dialogue,\nblah blah\nblah blah\nNAME a dialogue name".to_string();
+        let expected = "DLG y\nThis is a bit of dialogue,\nblah blah\nblah blah\nNAME a dialogue name";
 
         assert_eq!(output, expected);
     }

src/game.rs

@@ -223,7 +223,13 @@ impl Game {
             } else if segment.starts_with("ITM ") {
                 items.push(Item::from(segment));
             } else if segment.starts_with("DLG ") {
-                dialogues.push(Dialogue::from(segment));
+                let result = Dialogue::from_str(&segment);
+
+                if let Ok(dialogue) = result {
+                    dialogues.push(dialogue);
+                } else {
+                    warnings.push(result.unwrap_err());
+                }
             } else if segment.starts_with("END ") {
                 let result = Ending::from_str(&segment);
                 if let Ok(ending) = result {