Implement the comparison.

src/compare/diff.rs

@@ -425,6 +425,24 @@ fn compare_ast_node<'b, 's>(
     Ok(compare_result.into())
 }
 
+fn compare_property_quoted_string_required_value<'b, 's, 'x>(
+    emacs: &'b Token<'s>,
+    emacs_field: &'x str,
+    rust_value: &'s str,
+) -> Result<Option<(DiffStatus, Option<String>)>, Box<dyn std::error::Error>> {
+    let value = get_property_quoted_string(emacs, emacs_field)?;
+    if value.as_ref().map(String::as_str) != Some(rust_value) {
+        let this_status = DiffStatus::Bad;
+        let message = Some(format!(
+            "{} mismatch (emacs != rust) {:?} != {:?}",
+            emacs_field, value, rust_value
+        ));
+        Ok(Some((this_status, message)))
+    } else {
+        Ok(None)
+    }
+}
+
 pub fn compare_document<'b, 's>(
     emacs: &'b Token<'s>,
     rust: &'b Document<'s>,
@@ -2690,8 +2708,15 @@ fn compare_code<'b, 's>(
         ));
     }
 
-    let foo: Result<Option<(DiffStatus, Option<String>)>, Box<dyn std::error::Error>> =
-        compare_properties!(emacs, EmacsField::Required(":value"));
+    if let Some((new_status, new_message)) = compare_properties!(
+        emacs,
+        EmacsField::Required(":value"),
+        rust.contents,
+        compare_property_quoted_string_required_value
+    )? {
+        this_status = new_status;
+        message = new_message;
+    }
 
     Ok(DiffResult {
         status: this_status,