From 9b1f6a1dc11b55b161e8d6c2d7cd32d393d28815 Mon Sep 17 00:00:00 2001
From: Schrottkatze <git@schrottkatze.de>
Date: Mon, 21 Oct 2024 15:15:40 +0200
Subject: [PATCH] pawarser: Implement `CompletedMarker::precede`

---
 crates/pawarser/src/parser/marker.rs | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/crates/pawarser/src/parser/marker.rs b/crates/pawarser/src/parser/marker.rs
index 2d3fc5a..d03e358 100644
--- a/crates/pawarser/src/parser/marker.rs
+++ b/crates/pawarser/src/parser/marker.rs
@@ -69,6 +69,17 @@ pub struct CompletedMarker<SyntaxKind: SyntaxElement, SyntaxErr: SyntaxError> {
 
 impl<SyntaxKind: SyntaxElement, SyntaxErr: SyntaxError> CompletedMarker<SyntaxKind, SyntaxErr> {
     pub fn precede(self, p: &mut Parser<SyntaxKind, SyntaxErr>, name: &str) -> Marker {
-        todo!()
+        let new_pos = p.start(name);
+
+        match &mut p.events[self.pos] {
+            Event::Start { forward_parent, .. } => {
+                // point forward parent of the node this marker completed to the new node
+                // will later be used to make the new node a parent of the current node.
+                *forward_parent = Some(new_pos.pos - self.pos)
+            }
+            _ => unreachable!(),
+        }
+
+        new_pos
     }
 }