Compare the additional properties on headlines.

src/compare/util.rs

@@ -1,5 +1,6 @@
 use std::str::FromStr;
 
+use super::compare_field::ComparePropertiesResult;
 use super::diff::DiffEntry;
 use super::diff::DiffStatus;
 use super::elisp_fact::GetElispFact;
@@ -311,3 +312,28 @@ pub(crate) fn assert_no_children<'b, 's>(
     }
     Ok(())
 }
+
+pub(crate) fn compare_additional_properties<'b, 's, RK, RV, RI>(
+    emacs: &'b Token<'s>,
+    rust_children: RI,
+) -> Result<ComparePropertiesResult<'b, 's>, Box<dyn std::error::Error>>
+where
+    RK: AsRef<str>,
+    RV: AsRef<str>,
+    RI: Iterator<Item = (RK, RV)> + ExactSizeIterator,
+{
+    for (rust_key, rust_value) in rust_children {
+        let rust_key = rust_key.as_ref();
+        let rust_value = rust_value.as_ref();
+        let emacs_value = get_property_quoted_string(emacs, rust_key)?;
+        if Some(rust_value) != emacs_value.as_ref().map(String::as_str) {
+            let this_status = DiffStatus::Bad;
+            let message = Some(format!(
+                "{} mismatch (emacs != rust) {:?} != {:?}",
+                rust_key, emacs_value, rust_value
+            ));
+            return Ok(ComparePropertiesResult::SelfChange(this_status, message));
+        }
+    }
+    Ok(ComparePropertiesResult::NoChange)
+}