Support --- as document start

Signed-off-by: Gris Ge <[email protected]>

src/char_iter.rs

@@ -67,4 +67,8 @@ impl<'s> CharsIter<'s> {
             }
         }
     }
+
+    pub(crate) fn as_str(&self) -> &str {
+        self.iter.as_str()
+    }
 }

src/token.rs

@@ -142,6 +142,15 @@ impl YamlToken {
                 YAML_CHAR_SEQUENCE_ENTRY
                 | YAML_CHAR_MAPPING_KEY
                 | YAML_CHAR_MAPPING_VALUE => {
+                    // We might be got `---` as document begin which we should
+                    // ignore
+                    if iter.as_str().starts_with("---") {
+                        iter.next();
+                        iter.next();
+                        iter.next();
+                        continue;
+                    }
+
                     let indicator = match c {
                         YAML_CHAR_SEQUENCE_ENTRY => {
                             YamlTokenData::BlockSequenceIndicator

tests/from_str.rs

@@ -30,7 +30,7 @@ fn test_de_bool() -> Result<(), Box<dyn std::error::Error>> {
 
 #[test]
 fn test_de_unsign_number() -> Result<(), Box<dyn std::error::Error>> {
-    assert_eq!(123114u32, rmsd_yaml::from_str("123114")?);
+    assert_eq!(123114u32, rmsd_yaml::from_str("\n---\n123114")?);
 
     assert_eq!(1234u16, rmsd_yaml::from_str("+1234")?);
 
@@ -56,6 +56,7 @@ fn test_de_struct() -> Result<(), Box<dyn std::error::Error>> {
     }
 
     let yaml_str = r#"
+        ---
         uint_a: 500
         str_b: "abc"
         bar: