lang: rewrite parser

crates/lang/src/parser/events.rs

@@ -0,0 +1,23 @@
+use crate::parser::syntax_kind::SyntaxKind;
+
+#[derive(Debug)]
+pub enum Event {
+    Start {
+        kind: SyntaxKind,
+        forward_parent: Option<usize>,
+    },
+    Finish,
+    Eat {
+        count: usize,
+    },
+    Error,
+}
+
+impl Event {
+    pub(crate) fn tombstone() -> Self {
+        Self::Start {
+            kind: SyntaxKind::TOMBSTONE,
+            forward_parent: None,
+        }
+    }
+}