redo ending transformations

src/ending.rs

@@ -1,3 +1,7 @@
+use std::fmt;
+use std::error::Error;
+use std::str::FromStr;
+
 // same as a dialogue basically
 #[derive(Debug, Eq, PartialEq)]
 pub struct Ending {
@@ -5,32 +9,36 @@ pub struct Ending {
     dialogue: String,
 }
 
-impl From<String> for Ending {
-    #[inline]
-    fn from(string: String) -> Ending {
-        let lines: Vec<&str> = string.lines().collect();
+impl Error for Ending {}
+
+impl FromStr for Ending {
+    type Err = String;
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        let lines: Vec<&str> = s.lines().collect();
         let id = lines[0].replace("END ", "").to_string();
         let dialogue = lines[1..].join("\n");
 
-        Ending { id, dialogue }
+        Ok(Ending { id, dialogue })
     }
 }
 
-impl ToString for Ending {
+impl fmt::Display for Ending {
     #[inline]
-    fn to_string(&self) -> String {
-        format!("END {}\n{}", self.id, self.dialogue)
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(f,"END {}\n{}", self.id, self.dialogue)
     }
 }
 
 #[cfg(test)]
 mod test {
     use crate::ending::Ending;
+    use std::str::FromStr;
 
     #[test]
     fn test_ending_from_string() {
         assert_eq!(
-            Ending::from(include_str!("test-resources/ending").to_string()),
+            Ending::from_str(include_str!("test-resources/ending")).unwrap(),
             Ending {
                 id: "a".to_string(),
                 dialogue: "This is a long line of dialogue. Blah blah blah".to_string()

src/game.rs

@@ -1,6 +1,7 @@
 use crate::{Dialogue, Ending, Font, Item, Palette, Room, Sprite, TextDirection, Tile, ToBase36, Variable, transform_line_endings, segments_from_string, is_string_numeric};
 use std::error::Error;
 use loe::TransformMode;
+use std::str::FromStr;
 
 /// in very early versions of Bitsy, room tiles were defined as single characters
 /// so, only 36 tiles total. later versions are comma-separated
@@ -169,7 +170,10 @@ impl Game {
             } else if segment.starts_with("DLG ") {
                 dialogues.push(Dialogue::from(segment));
             } else if segment.starts_with("END ") {
-                endings.push(Ending::from(segment));
+                let ending = Ending::from_str(&segment);
+                if ending.is_ok() {
+                    endings.push(ending.unwrap());
+                }
             } else if segment.starts_with("VAR ") {
                 variables.push(Variable::from(segment));
             } else if segment.starts_with("FONT ") {