Record left-linear expansion and forest format

Now the grammar will record the left-linear expansions when generating
the nondeterministic finite automaton frmo its rules, and will record
whether an edge in the nondeterministic finite automaton comes from a
left-linear expansion.  The latter is needed because while performing
a chain-rule derivation, we do not need the left-linear expanded
derivations in the "first layer".  This might well have been the root
cause of the bad performance of the previous version of this package.

Also I have figured out how to properly generate and handle parse
forests while manipulating the "chain-rule machine".

1 files changed, 7 insertions, 2 deletions

diff --git a/graph/src/labelled/double.rs b/graph/src/labelled/double.rs
index 53b5dc8..4ab8a38 100644
--- a/graph/src/labelled/double.rs
+++ b/graph/src/labelled/double.rs
@@ -554,9 +554,14 @@ impl<T: GraphLabel> Builder for DLGBuilder<T> {
         Ok(())
     }
 
-    fn remove_edge<F>(&mut self, source: usize, target: usize, predicate: F) -> Result<(), Error>
+    fn remove_edge<F>(
+        &mut self,
+        source: usize,
+        target: usize,
+        mut predicate: F,
+    ) -> Result<(), Error>
     where
-        F: Fn(Self::Label) -> bool,
+        F: FnMut(Self::Label) -> bool,
     {
         let nodes_len = self.nodes.len();