export JMESExpr class

pyproject.toml

@@ -6,8 +6,8 @@ build-backend = "scikit_build_core.build"
 
 [project]
 name = "pybind11_jsoncons"
-version = "0.1.1"
-description="python binding for jsoncons (only what I needed for now)"
+version = "0.1.2"
+description="python binding for jsoncons + msgpack + jmespath (only what I needed for now)"
 readme = "README.md"
 authors = [
   { name = "zhixiong.tang", email = "dvorak4tzx@email.com" },

src/main.cpp

@@ -20,6 +20,7 @@
 using json = jsoncons::ojson; // using json = jsoncons::json;
 namespace jmespath = jsoncons::jmespath;
 namespace msgpack = jsoncons::msgpack;
+using jmespath_expr_type = jmespath::jmespath_expression<json>;
 
 namespace py = pybind11;
 using rvp = py::return_value_policy;
@@ -225,6 +226,19 @@ struct JsonQueryRepl {
         return result.to_string();
     }
 
+    /**
+     * Evaluate a JMESPath expression against the JSON document.
+     * @param expr JMESPath expression
+     * @return Result of the evaluation as a json object
+     */
+    json eval_expr(const jmespath_expr_type &expr) const {
+        auto result = expr.evaluate(doc, params_);
+        if (debug) {
+            std::cerr << pretty_print(result) << std::endl;
+        }
+        return result;
+    }
+
     /**
      * Add parameters for JMESPath evaluation.
      * @param key Parameter key
@@ -394,9 +408,13 @@ struct JsonQuery {
     std::vector<std::unique_ptr<jmespath::jmespath_expression<json>>> transforms_expr_;
     std::map<std::string, json> params_;
 
-
     std::deque<std::vector<json>> outputs_;
 
+    /**
+     * Internal method to check if a JSON document matches the predicate.
+     * @param msg JSON document to check
+     * @return True if the document matches the predicate, false otherwise
+     */
     bool __matches(const json &msg) const {
         auto ret = predicate_expr_->evaluate(msg, params_);
         return /*ret.is_bool() && */ ret.as_bool();
@@ -533,6 +551,15 @@ PYBIND11_MODULE(_core, m) {
             Returns:
                 str: Result of the evaluation as a string
         )pbdoc")
+        .def("eval_expr", &JsonQueryRepl::eval_expr, "expr"_a, R"pbdoc(
+            Evaluate a JMESPath expression against the JSON document.
+
+            Args:
+                expr: JMESPath expression
+
+            Returns:
+                json: Result of the evaluation as a json object
+        )pbdoc")
         .def("add_params", &JsonQueryRepl::add_params, "key"_a, "value"_a, R"pbdoc(
             Add parameters for JMESPath evaluation.
 
@@ -661,6 +688,26 @@ PYBIND11_MODULE(_core, m) {
             str: JSON string representation
     )pbdoc");
 
+    py::class_<jmespath_expr_type>(m, "JMESPathExpr", py::module_local(), py::dynamic_attr()) //
+        .def("evaluate", [](const jmespath_expr_type &self, const json &doc) -> json {
+            return self.evaluate(doc);
+        }, "doc"_a, R"pbdoc(
+            Evaluate the JMESPath expression against a JSON document.
+
+            Args:
+                doc: JSON document
+
+            Returns:
+                json: Result of the evaluation
+        )pbdoc")
+        //
+        .def_static("build", [](const std::string &expr_text) -> jmespath_expr_type {
+            return jmespath::make_expression<json>(expr_text);
+        }, "expr_text"_a, R"pbdoc(
+            Create a new JMESPath expression.
+        )pbdoc")
+        ;
+
     // m.def("dumps", [](const json &json_val) -> std::string {
     //     return json_val.to_string();
     // });

src/pybind11_jsoncons/__init__.py

@@ -1,6 +1,7 @@
 from __future__ import annotations
 
 from ._core import (
+    JMESPathExpr,
     Json,
     JsonQuery,
     JsonQueryRepl,
@@ -15,6 +16,7 @@
     "__version__",
     "JsonQuery",
     "JsonQueryRepl",
+    "JMESPathExpr",
     "Json",
     "msgpack_decode",
     "msgpack_encode",

src/pybind11_jsoncons/__init__.pyi

@@ -72,17 +72,38 @@ class Json:
         """
         Convert a Python object to a JSON object.
 
+        This method converts various Python types to their JSON equivalents:
+        - None -> null
+        - bool -> boolean
+        - int -> integer
+        - float -> number
+        - str -> string
+        - list/tuple -> array
+        - dict -> object
+
         Args:
             obj: Python object to convert
 
         Returns:
-            Json: Reference to self
+            Json: Reference to self with converted data
+
+        Raises:
+            RuntimeError: If the Python object contains circular references or unsupported types
         """
 
     def to_python(self) -> Any:
         """
         Convert a JSON object to a Python object.
 
+        This method converts JSON types to their Python equivalents:
+        - null -> None
+        - boolean -> bool
+        - integer -> int
+        - number -> float
+        - string -> str
+        - array -> list
+        - object -> dict
+
         Returns:
             Any: Python object representation of the JSON data
         """
@@ -122,6 +143,17 @@ class JsonQueryRepl:
             str: Result of the evaluation as a string
         """
 
+    def eval_expr(self, expr: JMESPathExpr) -> Json:
+        """
+        Evaluate a JMESPath expression against the JSON document.
+
+        Args:
+            expr: JMESPath expression
+
+        Returns:
+            Json: Result of the evaluation as a json object
+        """
+
     def add_params(self, key: str, value: str) -> None:
         """
         Add parameters for JMESPath evaluation.
@@ -241,6 +273,34 @@ class JsonQuery:
         Clear all processed data.
         """
 
+class JMESPathExpr:
+    """
+    A class representing a compiled JMESPath expression.
+    """
+
+    def evaluate(self, doc: Json) -> Json:
+        """
+        Evaluate the JMESPath expression against a JSON document.
+
+        Args:
+            doc: JSON document
+
+        Returns:
+            Json: Result of the evaluation
+        """
+
+    @staticmethod
+    def build(expr_text: str) -> JMESPathExpr:
+        """
+        Create a new JMESPath expression.
+
+        Args:
+            expr_text: JMESPath expression text
+
+        Returns:
+            JMESPathExpr: Compiled JMESPath expression
+        """
+
 def msgpack_decode(msgpack_bytes: bytes) -> str:
     """
     Convert MessagePack binary data to a JSON string.

tests/test_basic.py

@@ -8,7 +8,7 @@
 
 
 def test_version():
-    assert m.__version__ == "0.1.1"
+    assert m.__version__ == "0.1.2"
 
 
 def test_repl():
@@ -95,6 +95,18 @@ def test_json_query():
     assert json.loads(repl.eval("name")) == "Baby"
     assert not json.loads(repl.eval("age >= `18`"))
 
+    assert repl.doc.to_json() == '{"age":5,"other":"too young","name":"Baby"}'
+    repl.doc.from_python(people[1])
+    assert repl.doc.to_json() == '{"age":20,"other":"foo","name":"Bob"}'
+    repl.debug = False
+    assert not repl.debug
+    assert repl.eval("age == `20`") == "true"
+
+    expr = m.JMESPathExpr.build("age == `20`")
+    assert isinstance(expr, m.JMESPathExpr)
+    assert expr.evaluate(m.Json().from_python(people[1])).to_python()
+    assert repl.eval_expr(expr).to_python()
+
     jql = m.JsonQuery()
     with pytest.raises(RuntimeError) as excinfo:
         jql.setup_predicate("[*].[")