Starting a compare properties document function.

src/compare/util.rs

@@ -284,6 +284,39 @@ where
     Ok(())
 }
 
+pub(crate) fn compare_children_iter<
+    'b,
+    's,
+    'x,
+    RC: 'x,
+    RI: Iterator<Item = &'x RC> + ExactSizeIterator,
+>(
+    source: &'s str,
+    emacs: &'b Token<'s>,
+    rust_children: RI,
+    child_status: &mut Vec<DiffEntry<'b, 's>>,
+    this_status: &mut DiffStatus,
+    message: &mut Option<String>,
+) -> Result<(), Box<dyn std::error::Error>>
+where
+    AstNode<'b, 's>: From<&'x RC>,
+{
+    let emacs_children = emacs.as_list()?;
+    let emacs_children_length = emacs_children.len() - 2;
+    if emacs_children_length != rust_children.len() {
+        *this_status = DiffStatus::Bad;
+        *message = Some(format!(
+            "Child length mismatch (emacs != rust) {:?} != {:?}",
+            emacs_children_length,
+            rust_children.len()
+        ));
+    }
+    for (emacs_child, rust_child) in emacs_children.iter().skip(2).zip(rust_children) {
+        child_status.push(compare_ast_node(source, emacs_child, rust_child.into())?);
+    }
+    Ok(())
+}
+
 pub(crate) fn assert_no_children<'b, 's>(
     emacs: &'b Token<'s>,
     this_status: &mut DiffStatus,