Getting weird errors from the not()s.

src/parser/new_context.rs

@@ -1,4 +1,8 @@
+use std::borrow::Cow;
+
+use nom::combinator::not;
 use nom::combinator::recognize;
+use nom::complete::take;
 use nom::error::VerboseError;
 use nom::IResult;
 
@@ -9,7 +13,7 @@ type Matcher = dyn for<'s> Fn(&'s str) -> IResult<&'s str, &'s str, VerboseError
 type Link<'r, T> = Option<&'r Node<'r, T>>;
 
 pub trait OrgModeContext<'r> {
-    // todo
+    fn get_fail_matcher(&'r self) -> Cow<ChainBehavior<'r>>;
 }
 
 struct FailMatcherNode<'r> {
@@ -20,7 +24,8 @@ struct PreviousElementNode<'r> {
     dummy: &'r str,
 }
 
-enum ChainBehavior<'r> {
+#[derive(Clone)]
+pub enum ChainBehavior<'r> {
     AndParent(Option<&'r Matcher>),
     IgnoreParent(Option<&'r Matcher>),
 }
@@ -52,10 +57,56 @@ impl<'r> ContextTree<'r, dyn OrgModeContext<'r>> {
             head: Some(new_node),
         }
     }
+
+    pub fn check_fail_matcher<'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.expect("while loop asserts current_node is some.");
+            let current_fail_matcher = current_node_unwrapped.elem.get_fail_matcher();
+            match current_fail_matcher.as_ref() {
+                ChainBehavior::AndParent(Some(matcher)) => {
+                    let local_result = matcher(i);
+                    if local_result.is_ok() {
+                        return local_result;
+                    }
+                }
+                ChainBehavior::AndParent(None) => {}
+                ChainBehavior::IgnoreParent(Some(matcher)) => {
+                    let local_result = matcher(i);
+                    if local_result.is_ok() {
+                        return local_result;
+                    }
+                    // TODO: Make this a custom error
+                    not(take(0usize))(i)?;
+                }
+                ChainBehavior::IgnoreParent(None) => {
+                    // TODO: Make this a custom error
+                    not(take(0usize))(i)?;
+                }
+            };
+            current_node = current_node.map(|current_head| current_head.parent).flatten();
+        }
+        // TODO: Make this a custom error
+        not(take(0usize))(i)?;
+        unreachable!()
+    }
 }
 
-impl<'r> OrgModeContext<'r> for FailMatcherNode<'r> {}
-impl<'r> OrgModeContext<'r> for PreviousElementNode<'r> {}
+impl<'r> OrgModeContext<'r> for FailMatcherNode<'r> {
+    fn get_fail_matcher(&'r self) -> Cow<ChainBehavior<'r>> {
+        Cow::Borrowed(&self.fail_matcher)
+    }
+}
+
+impl<'r> OrgModeContext<'r> for PreviousElementNode<'r> {
+    fn get_fail_matcher(&'r self) -> Cow<ChainBehavior<'r>> {
+        todo!()
+    }
+}
 
 fn recognize_bold_end(input: &str) -> Res<&str, &str> {
     recognize(bold_end)(input)