Start of working on enum.

src/parser/nom_context.rs

@@ -42,7 +42,12 @@ impl<'r, T> ContextTree<'r, T> {
     }
 }
 
-pub struct ContextElement<'r> {
+pub enum ContextElement<'r> {
+    FailMatcherNode(FailMatcherNode<'r>),
+    PreviousElementNode(PreviousElementNode<'r>),
+}
+
+pub struct FailMatcherNode<'r> {
     pub fail_matcher: ChainBehavior<'r>,
 }
 
@@ -50,6 +55,7 @@ pub struct PreviousElementNode<'r> {
     pub dummy: &'r str,
 }
 
+#[derive(Clone)]
 pub enum ChainBehavior<'r> {
     AndParent(Option<&'r Matcher>),
     IgnoreParent(Option<&'r Matcher>),
@@ -66,9 +72,9 @@ impl<'r> OrgModeContextTree<'r> for OrgModeContextNode<'r> {
         &'r self,
         fail_matcher: &'r Matcher,
     ) -> ContextTree<'r, ContextElement<'r>> {
-        self.with_additional_node(ContextElement {
+        self.with_additional_node(ContextElement::FailMatcherNode(FailMatcherNode {
             fail_matcher: ChainBehavior::AndParent(Some(fail_matcher)),
-        })
+        }))
     }
 
     // fn with_previous_element(&'r self, dummy: &'r str) -> ContextTree<'r, PreviousElementNode<'r>> {
@@ -80,10 +86,9 @@ impl<'r> OrgModeContextTree<'r> for OrgModeContextNode<'r> {
     fn match_fail<'s>(&'r self, i: &'s str) -> IResult<&'s str, &'s str, VerboseError<&'s str>> {
         let mut current_node = self.head.as_ref();
         while current_node.is_some() {
-            let current_node_unwrapped = current_node
-                .as_ref()
-                .expect("while loop asserts current_node is some.");
-            match current_node_unwrapped.elem.fail_matcher {
+            let current_node_unwrapped =
+                current_node.expect("while loop asserts current_node is some.");
+            match current_node_unwrapped.elem.get_fail_matcher() {
                 ChainBehavior::AndParent(Some(matcher)) => {
                     let local_result = matcher(i);
                     if local_result.is_ok() {
@@ -117,3 +122,16 @@ impl<'r, T> std::fmt::Debug for ContextTree<'r, T> {
         write!(f, "ContextTree")
     }
 }
+
+impl<'r> ContextElement<'r> {
+    pub fn get_fail_matcher(&self) -> ChainBehavior<'r> {
+        match self {
+            ContextElement::FailMatcherNode(fail_matcher_node) => {
+                fail_matcher_node.fail_matcher.clone()
+            }
+            ContextElement::PreviousElementNode(previous_element_node) => {
+                ChainBehavior::AndParent(None)
+            }
+        }
+    }
+}