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, 0 insertions, 1 deletions

diff --git a/grammar/src/test_grammar_helper.rs b/grammar/src/test_grammar_helper.rs
index c236952..89f9844 100644
--- a/grammar/src/test_grammar_helper.rs
+++ b/grammar/src/test_grammar_helper.rs
@@ -275,7 +275,6 @@ pub fn new_paren_grammar() -> Result<Grammar, Box<dyn std::error::Error>> {
 }
 
 /// Return a left recursive grammar.
-#[allow(dead_code)]
 pub fn new_left_recursive_grammar() -> Result<Grammar, Box<dyn std::error::Error>> {
     let ter = vec![Terminal::new("B".to_owned()), Terminal::new("C".to_owned())];
     let non = vec![