PR remarks

core/json/json_path.rs

@@ -6,19 +6,24 @@ use pest_derive::Parser;
 #[grammar = "json/json_path.pest"]
 struct Parser;
 
-#[derive(Clone, Debug, PartialEq)]
-pub enum PathElement {
-    Root(),
-    Key(String),
-    ArrayLocator(i32),
-}
-
+/// Describes a JSON path, which is a sequence of keys and/or array locators.
 #[derive(Debug)]
 pub struct JsonPath {
     pub elements: Vec<PathElement>,
 }
 
-// Parses path into a Vec of Strings, where each string is a key or an array locator.
+/// PathElement describes a single element of a JSON path.
+#[derive(Clone, Debug, PartialEq)]
+pub enum PathElement {
+    /// Root element: '$'
+    Root(),
+    /// JSON key
+    Key(String),
+    /// Array locator, eg. [2], [#-5]
+    ArrayLocator(i32),
+}
+
+/// Parses path into a Vec of Strings, where each string is a key or an array locator.
 pub fn json_path(path: &str) -> crate::Result<JsonPath> {
     let parsed = Parser::parse(Rule::path, path);
 

core/json/mod.rs

@@ -185,7 +185,7 @@ pub fn json_extract(value: &OwnedValue, paths: &[OwnedValue]) -> crate::Result<O
     }
 
     if paths.len() > 1 {
-        result.pop();
+        result.pop(); // remove the final comma
         result.push(']');
     }
 

testing/json.test

@@ -113,6 +113,18 @@ do_execsql_test json_extract_number {
     SELECT json_extract(1, '$')
 } {{1}}
 
+do_execsql_test json_extract_object_1 {
+    SELECT json_extract('{"a": [1,2,3]}', '$.a')
+} {{[1,2,3]}}
+
+do_execsql_test json_extract_object_2 {
+    SELECT json_extract('{"a": [1,2,3]}', '$.a', '$.a[0]', '$.a[1]', '$.a[3]')
+} {{[[1,2,3],1,2,null]}}
+
+do_execsql_test json_extract_object_3 {
+    SELECT json_extract('{"a": [1,2,3]}', '$.a', '$.a[0]', '$.a[1]', null, '$.a[3]')
+} {{}}
+
 # TODO: fix me
 # \x61 is the ASCII code for 'a'
 # do_execsql_test json_extract_with_escaping {