Add the with_additional_node function to the ContextTree.

src/parser/list.rs

@@ -23,7 +23,7 @@ impl<T> List<T> {
         }
     }
 
-    pub fn get_data(&self) -> &T {
+    pub fn get_data(&self) -> Option<&T> {
-        &self.data
+        self.head.map(|rc_node| &rc_node.as_ref().data)
     }
 }

src/parser/new_context.rs

@@ -13,6 +13,13 @@ impl<'r> ContextTree<'r> {
     pub fn new() -> Self {
         ContextTree { tree: List::new() }
     }
+
+    pub fn with_additional_node<'x>(&self, data: ContextElement<'x>) -> ContextTree<'x> {
+        let new_list = self.tree.push_front(data);
+        ContextTree {
+            tree: new_list,
+        }
+    }
 }
 
 pub enum ContextElement<'r> {

src/parser/text_element_parser.rs

@@ -83,7 +83,7 @@ where
 pub fn document(input: &str) -> Res<&str, Vec<(Vec<TextElement>, &str)>> {
     let initial_context: ContextTree<'_> = ContextTree::new();
     let paragraph_parser = parser_with_context!(paragraph);
-    let ret = many1(paragraph_parser(&initial_context))(input);
+    let ret = many1(paragraph_parser(initial_context))(input);
     ret
 }