Make the fail matcher code in the new context tree work.

src/parser/new_context.rs

@@ -1,10 +1,11 @@
-use std::borrow::Cow;
-
 use nom::combinator::not;
 use nom::combinator::recognize;
 use nom::complete::take;
+use nom::error::ErrorKind;
+use nom::error::ParseError;
 use nom::error::VerboseError;
 use nom::IResult;
+use std::borrow::Cow;
 
 use super::text::bold_end;
 use super::text::Res;
@@ -76,23 +77,25 @@ impl<'r> ContextTree<'r, dyn OrgModeContext<'r>> {
                 }
                 ChainBehavior::AndParent(None) => {}
                 ChainBehavior::IgnoreParent(Some(matcher)) => {
-                    let local_result = matcher(i);
+                    return 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)?;
+                    return Err(nom::Err::Error(VerboseError::from_error_kind(
+                        i,
+                        ErrorKind::ManyTill,
+                    )));
                 }
             };
-            current_node = current_node.map(|current_head| current_head.parent).flatten();
+            current_node = current_node
+                .map(|current_head| current_head.parent)
+                .flatten();
         }
         // TODO: Make this a custom error
-        not(take(0usize))(i)?;
+        return Err(nom::Err::Error(VerboseError::from_error_kind(
-        unreachable!()
+            i,
+            ErrorKind::ManyTill,
+        )));
     }
 }
 
@@ -104,7 +107,7 @@ impl<'r> OrgModeContext<'r> for FailMatcherNode<'r> {
 
 impl<'r> OrgModeContext<'r> for PreviousElementNode<'r> {
     fn get_fail_matcher(&'r self) -> Cow<ChainBehavior<'r>> {
-        todo!()
+        Cow::Owned(ChainBehavior::AndParent(None))
     }
 }
 
@@ -122,3 +125,9 @@ fn test_context() {
     };
     let child2 = child1.with_additional_node(&child2_context);
 }
+
+impl<'r, T> std::fmt::Debug for ContextTree<'r, T> {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "ContextTree")
+    }
+}