Mainly worked on the rule matcher

Also fixed the name collector, and lambda parameters are no longer
resolved at parsing to support planned macro-based pattern matching.
The rule matcher clones a lot, the number of clones could be zero.

src/utils/mod.rs

@@ -1,6 +1,12 @@
 mod cache;
 mod substack;
+mod side;
+mod merge_sorted;
+mod sorted_pairs;
+mod unwrap_or_continue;
 pub use cache::Cache;
-pub use substack::Substack;
+pub use substack::Stackframe;
+pub use side::Side;
+pub use merge_sorted::merge_sorted;
 
 pub type BoxedIter<'a, T> = Box<dyn Iterator<Item = T> + 'a>;