Initial code structure for property drawers.

src/compare/diff.rs

@@ -1,7 +1,6 @@
 use super::sexp::Token;
 use super::util::assert_bounds;
 use super::util::assert_name;
-use crate::compare::util::get_offsets;
 use crate::parser::Comment;
 use crate::parser::Document;
 use crate::parser::DocumentElement;
@@ -13,6 +12,7 @@ use crate::parser::Heading;
 use crate::parser::Paragraph;
 use crate::parser::PlainList;
 use crate::parser::PlainListItem;
+use crate::parser::PropertyDrawer;
 use crate::parser::Section;
 use crate::DynamicBlock;
 
@@ -197,6 +197,7 @@ fn compare_element<'s>(
         Element::FootnoteDefinition(obj) => compare_footnote_definition(source, emacs, obj),
         Element::Comment(obj) => compare_comment(source, emacs, obj),
         Element::Drawer(obj) => compare_drawer(source, emacs, obj),
+        Element::PropertyDrawer(obj) => compare_property_drawer(source, emacs, obj),
     }
 }
 
@@ -428,3 +429,33 @@ fn compare_drawer<'s>(
         children: child_status,
     })
 }
+
+fn compare_property_drawer<'s>(
+    source: &'s str,
+    emacs: &'s Token<'s>,
+    rust: &'s PropertyDrawer<'s>,
+) -> Result<DiffResult, Box<dyn std::error::Error>> {
+    let children = emacs.as_list()?;
+    let mut child_status = Vec::new();
+    let mut this_status = DiffStatus::Good;
+    let emacs_name = "property-drawer";
+    if assert_name(emacs, emacs_name).is_err() {
+        this_status = DiffStatus::Bad;
+    }
+
+    if assert_bounds(source, emacs, rust).is_err() {
+        this_status = DiffStatus::Bad;
+    }
+
+    for (emacs_child, rust_child) in children.iter().skip(2).zip(rust.children.iter()) {
+        // TODO: What are node properties and are they the only legal child of property drawers?
+        // child_status.push(compare_element(source, emacs_child, rust_child)?);
+    }
+
+    Ok(DiffResult {
+        status: this_status,
+        name: emacs_name.to_owned(),
+        message: None,
+        children: child_status,
+    })
+}