Add debugging helpers.

parser/examples/dump_events.rs

@@ -16,6 +16,7 @@ struct EventSink {
 
 impl MarkedEventReceiver for EventSink {
     fn on_event(&mut self, ev: Event, mark: Marker) {
+        eprintln!("    \x1B[;34m\u{21B3} {:?}\x1B[;m", &ev);
         self.events.push((ev, mark));
     }
 }
@@ -34,5 +35,6 @@ fn main() {
     let mut s = String::new();
     f.read_to_string(&mut s).unwrap();
 
-    dbg!(str_to_events(&s));
+    // dbg!(str_to_events(&s));
+    str_to_events(&s);
 }

parser/src/scanner.rs

@@ -244,6 +244,12 @@ impl<T: Iterator<Item = char>> Iterator for Scanner<T> {
             return None;
         }
         match self.next_token() {
+            Ok(Some(tok)) => {
+                if std::env::var("YAMLRUST_DEBUG").is_ok() {
+                    eprintln!("\x1B[;32m{:?} \x1B[;36m{:?}\x1B[;m", tok.1, tok.0);
+                }
+                Some(tok)
+            }
             Ok(tok) => tok,
             Err(e) => {
                 self.error = Some(e);

parser/tests/spec_test.rs

@@ -59,7 +59,7 @@ macro_rules! assert_next {
         match $v.next().unwrap() {
             $p => {}
             e => {
-                panic!("unexpected event: {:?}", e);
+                panic!("unexpected event: {:?} (expected {:?})", e, stringify!($p));
             }
         }
     };