Starting to create a WalkError type for walking that will not bubble up.

src/renderer/errors.rs

@@ -15,6 +15,17 @@ pub enum RenderError<'a> {
     },
 }
 
+pub enum WalkError<'a> {
+    CantWalk {
+        segment: String,
+        elem: &'a dyn ContextElement,
+    },
+    NotFound {
+        path: &'a Vec<&'a str>,
+        breadcrumbs: Vec<&'a dyn ContextElement>,
+    },
+}
+
 #[derive(Clone)]
 pub struct CompileError {
     pub message: String,
@@ -54,6 +65,38 @@ impl error::Error for RenderError<'_> {
     }
 }
 
+impl fmt::Display for WalkError<'_> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        match self {
+            WalkError::CantWalk { segment, elem } => {
+                write!(f, "Tried to walk to {} from {:?}", segment, elem)
+            }
+            WalkError::NotFound { path, breadcrumbs } => {
+                write!(f, "Could not find {:?} in {:?}", path, breadcrumbs)
+            }
+        }
+    }
+}
+
+impl fmt::Debug for WalkError<'_> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        match self {
+            WalkError::CantWalk { segment, elem } => {
+                write!(f, "Tried to walk to {} from {:?}", segment, elem)
+            }
+            WalkError::NotFound { path, breadcrumbs } => {
+                write!(f, "Could not find {:?} in {:?}", path, breadcrumbs)
+            }
+        }
+    }
+}
+
+impl error::Error for WalkError<'_> {
+    fn source(&self) -> Option<&(dyn error::Error + 'static)> {
+        None
+    }
+}
+
 impl fmt::Display for CompileError {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         write!(f, "Error compiling: {}", self.message)