add AsRef, expose object and array iter on Value (#2207)

add AsRef
expose object and array iter
add to_json on Document

src/schema/document/default_doc_type.rs

@@ -195,14 +195,6 @@ impl TantivyDocument {
         Ok(document)
     }
 
-    /// Encode the schema in JSON.
-    ///
-    /// Encoding a document cannot fail.
-    pub fn to_json(&self, schema: &Schema) -> String {
-        serde_json::to_string(&self.to_named_doc(schema))
-            .expect("doc encoding failed. This is a bug")
-    }
-
     /// Build a document object from a json-object.
     pub fn parse_json(schema: &Schema, doc_json: &str) -> Result<TantivyDocument, DocParsingError> {
         let json_obj: Map<String, serde_json::Value> =

src/schema/document/mod.rs

@@ -235,6 +235,14 @@ pub trait Document: DocumentDeserialize + Send + Sync + 'static {
         }
         NamedFieldDocument(field_map)
     }
+
+    /// Encode the doc in JSON.
+    ///
+    /// Encoding a document cannot fail.
+    fn to_json(&self, schema: &Schema) -> String {
+        serde_json::to_string(&self.to_named_doc(schema))
+            .expect("doc encoding failed. This is a bug")
+    }
 }
 
 /// A single field value.
@@ -357,6 +365,26 @@ pub trait Value<'a>: Send + Sync + Debug {
         }
     }
 
+    #[inline]
+    /// Returns the iterator over the array if the Value is an array.
+    fn as_array(&self) -> Option<Self::ArrayIter> {
+        if let ReferenceValue::Array(val) = self.as_value() {
+            Some(val)
+        } else {
+            None
+        }
+    }
+
+    #[inline]
+    /// Returns the iterator over the object if the Value is an object.
+    fn as_object(&self) -> Option<Self::ObjectIter> {
+        if let ReferenceValue::Object(val) = self.as_value() {
+            Some(val)
+        } else {
+            None
+        }
+    }
+
     #[inline]
     /// Returns true if the Value is an array.
     fn is_array(&self) -> bool {