before a major refactor

I decide to adopt a new approach of recording and updating item
derivation forests.  Since this affects a lot of things, I decide to
commit before the refactor, so that I can create a branch for that
refactor.

1 files changed, 6 insertions, 0 deletions

diff --git a/grammar/src/label.rs b/grammar/src/label.rs
index 058baaf..e3f3422 100644
--- a/grammar/src/label.rs
+++ b/grammar/src/label.rs
@@ -119,6 +119,12 @@ impl GrammarLabel {
         self.end
     }
 
+    /// Set the start.
+    #[inline]
+    pub fn set_start(&mut self, pos: usize) {
+        self.start = pos;
+    }
+
     /// Return the start in the input.
     #[inline]
     pub fn start(&self) -> usize {