--- a/src/matcher.rs	Sat Aug 31 21:00:53 2019 +0200
+++ b/src/matcher.rs	Sun Sep 01 20:44:33 2019 +0200
@@ -3,7 +3,7 @@
 #![allow(dead_code)]
 
 use std::fmt::Debug;
-use std::iter::FromIterator;
+use std::iter::{self, FromIterator};
 use std::rc::Rc;
 
 /// Matchee contains a character and position to match. It's used by the matching logic to check
@@ -46,6 +46,11 @@
     pub fn finished(&self) -> bool {
         self.ix == self.src.len()
     }
+    pub fn string(&self) -> String {
+        let matchee = String::from_iter(self.src.iter());
+        let pointer = String::from_iter(iter::repeat(' ').take(self.ix).chain(iter::once('^')));
+        format!("{}\n{}", matchee, pointer)
+    }
 }
 
 /// A Matcher matches parts of a Matchee (where a Matchee is a string to be matched). While

--- a/src/matching.rs	Sat Aug 31 21:00:53 2019 +0200
+++ b/src/matching.rs	Sun Sep 01 20:44:33 2019 +0200
@@ -24,6 +24,7 @@
     submatches: Rc<RefCell<Vec<Option<usize>>>>,
     // We need to clone the submatches queue only rarely (when a submatch starts or ends).
     submatches_todo: Rc<Vec<usize>>,
+    debug: bool,
 }
 
 impl MatchState {
@@ -33,6 +34,7 @@
             matchee: Matchee::from_string(s),
             submatches: Rc::new(RefCell::new(vec![None; s.len()])),
             submatches_todo: Rc::new(Vec::with_capacity(4)),
+            debug: false,
         }
     }
     fn fork(&self, next: StateRef, advance: usize) -> MatchState {
@@ -65,6 +67,13 @@
             self.submatches.borrow_mut()[begin] = Some(self.matchee.pos());
         }
     }
+    fn debug(&self, sg: &StateGraph) -> String {
+        let m = self.matchee.string();
+        let out = sg[self.node].out.map_or("".to_owned(), |ix| sg[ix].to_string());
+        let out1 = sg[self.node].out1.map_or("".to_owned(), |ix| sg[ix].to_string());
+        let full = format!("{}   (<{}> next: 1. <{:?}> {} 2. <{:?}> {})\n", m, self.node, sg[self.node].out, out, sg[self.node].out1, out1);
+        full
+    }
 }
 
 /// do_match starts the matching process. It tries to match the supplied compiled regex against the

--- a/src/state.rs	Sat Aug 31 21:00:53 2019 +0200
+++ b/src/state.rs	Sun Sep 01 20:44:33 2019 +0200
@@ -71,7 +71,7 @@
         (self.out.clone(), self.out1.clone())
     }
 
-    fn to_string(&self) -> String {
+    pub fn to_string(&self) -> String {
         format!(
             "m:{} sub:{}",
             if let Some(ref m) = self.matcher {