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, 2 insertions, 2 deletions

diff --git a/chain/src/atom/mod.rs b/chain/src/atom/mod.rs
index 084acca..065640b 100644
--- a/chain/src/atom/mod.rs
+++ b/chain/src/atom/mod.rs
@@ -7,10 +7,10 @@
 //! I have better ideas in the future.
 
 use grammar::{Error as GrammarError, TNT};
-use nfa::{DOption, Nfa};
+use nfa::{DOption, LabelType, Nfa};
 
 /// The expected behaviours of an atomic language.
-pub trait Atom: Nfa<DOption<TNT>> {
+pub trait Atom: Nfa<LabelType<TNT>> {
     /// Return the index of a node representing the derivative of the
     /// left-linear null closure of `nt` with respect to `t`.
     fn atom(&self, nt: usize, t: usize) -> Result<Option<usize>, GrammarError>;