Add support for nested operators inside arrays (#25)

Author: Viicos

docs/source/conf.py

@@ -13,7 +13,7 @@
 project = "python-jsonlogic"
 copyright = "2024, Victorien"
 author = "Victorien"
-release = "0.1"
+release = "0.0.1"
 
 # -- General configuration ---------------------------------------------------
 # https://www.sphinx-doc.org/en/master/usage/configuration.html#general-configuration

docs/source/usage/evaluation.rst

@@ -13,7 +13,6 @@ using the utility :func:`~jsonlogic.evaluation.evaluate` function:
     expr = JSONLogicExpression.from_json({">": [{"var": "my_int"}, 2]})
 
     root_op = expr.as_operator_tree(operator_registry)
-    assert isinstance(root_op, Operator)
 
     return_value = evaluate(
         root_op,

docs/source/usage/index.rst

@@ -74,10 +74,6 @@ receives two arguments:
 - :paramref:`~jsonlogic.core.Operator.from_expression.arguments`: The list of arguments for this operator.
   This can either be another :class:`~jsonlogic.core.Operator` or a :data:`~jsonlogic.typing.JSONLogicPrimitive`.
 
-Note that because this method is defined recursively, the retun type annotation is the union
-of :class:`~jsonlogic.core.Operator` and :data:`~jsonlogic.typing.JSONLogicPrimitive`. Using
-an :keyword:`assert` statement or :func:`~typing.cast` call might help your type checker.
-
 .. warning::
 
     Each operator is responsible for checking the provided arguments. For example, the ``GreaterThan`` operator

docs/source/usage/resolving_variables.rst

@@ -43,9 +43,9 @@ the expression will evaluate to :json:`1`. However, this dot-like notation can b
           "some.var": 2
       }
 
-For this reason, an alternative format is proposed, based on the JSON Pointer standard (:rfc:`6901`). The following expressions:
+For this reason, an alternative format is proposed, based on the JSON Pointer standard (:rfc:`6901`).
 
-with the following data:
+With the following data:
 
 .. code-block:: json
 
@@ -71,7 +71,7 @@ this is how the references will evaluate:
 Variables scopes
 ----------------
 
-The original `JsonLogic`_ format implicitly uses the notion scope in the implementation
+The original `JsonLogic`_ format implicitly uses the notion of a scope in the implementation
 of some operators such as `map <https://jsonlogic.com/operations.html#map-reduce-and-filter>`_:
 
 .. code-block:: json

docs/source/usage/typechecking.rst

@@ -22,7 +22,6 @@ can be used:
     expr = JSONLogicExpression.from_json({">": [{"var": "my_int"}, 2]})
 
     root_op = expr.as_operator_tree(operator_registry)
-    assert isinstance(root_op, Operator)
 
     root_type, diagnostics = typecheck(
         root_op,

src/jsonlogic/core.py

@@ -10,7 +10,7 @@
 
 from ._compat import Self, TypeAlias
 from .json_schema.types import AnyType, JSONSchemaType
-from .typing import JSON, JSONLogicPrimitive, OperatorArgument
+from .typing import JSON, JSONLogicPrimitive, JSONObject, OperatorArgument
 
 if TYPE_CHECKING:
     # This is a hack to make Pylance think `TypeAlias` comes from `typing`
@@ -62,27 +62,35 @@ def __init__(self, message: str, /) -> None:
         self.message = message
 
 
-NormalizedExpression: TypeAlias = "dict[str, list[JSONLogicExpression]]"
+ExprArgument: TypeAlias = "JSONLogicPrimitive | JSONLogicExpression | list[ExprArgument]"
+
+NormalizedExpression: TypeAlias = "dict[str, list[ExprArgument]]"
 
 
 @dataclass
 class JSONLogicExpression:
     """A parsed and normalized JSON Logic expression.
 
-    A JSON Logic expression can be:
-
-    - a single item dictionary, mapping the operator key to another :class:`JSONLogicExpression`,
-    - a :data:`~jsonlogic.typing.JSONLogicPrimitive`.
+    The underlying structure of an expression is a single item dictionary,
+    mapping the operator key to a list of arguments.
 
     All JSON Logic expressions should be instantiated using the :meth:`from_json` constructor::
 
-        expr = JSONLogicExpression.from_json(...)
+        expr = JSONLogicExpression.from_json({"op": ...})
     """
 
-    expression: JSONLogicPrimitive | NormalizedExpression
+    expression: NormalizedExpression
+
+    @classmethod
+    def _parse_impl(cls, json: JSON) -> ExprArgument:
+        if isinstance(json, dict):
+            return cls.from_json(json)
+        if isinstance(json, list):
+            return [cls._parse_impl(s) for s in json]
+        return json
 
     @classmethod
-    def from_json(cls, json: JSON) -> Self:  # TODO disallow list? TODO fix type errors
+    def from_json(cls, json: JSONObject) -> Self:
         """Build a JSON Logic expression from JSON data.
 
         Operator arguments are recursively normalized to a :class:`list`::
@@ -91,30 +99,34 @@ def from_json(cls, json: JSON) -> Self:  # TODO disallow list? TODO fix type err
             assert expr.expression == {"var": ["varname"]}
         """
         if not isinstance(json, dict):
-            return cls(expression=json)  # type: ignore
+            raise ValueError("The root node of the expression must be a dict")
 
         operator, op_args = next(iter(json.items()))
         if not isinstance(op_args, list):
             op_args = [op_args]
 
-        sub_expressions = [cls.from_json(op_arg) for op_arg in op_args]
+        return cls({operator: [cls._parse_impl(arg) for arg in op_args]})
 
-        return cls({operator: sub_expressions})  # type: ignore
+    def _as_op_impl(self, op_arg: ExprArgument, operator_registry: OperatorRegistry) -> OperatorArgument:
+        if isinstance(op_arg, JSONLogicExpression):
+            return op_arg.as_operator_tree(operator_registry)
+        if isinstance(op_arg, list):
+            return [self._as_op_impl(sub_arg, operator_registry) for sub_arg in op_arg]
+        return op_arg
 
-    def as_operator_tree(self, operator_registry: OperatorRegistry) -> JSONLogicPrimitive | Operator:
+    def as_operator_tree(self, operator_registry: OperatorRegistry) -> Operator:
         """Return a recursive tree of operators, using the provided registry as a reference.
 
         Args:
             operator_registry: The registry to use to resolve operator IDs.
 
         Returns:
-            The current expression if it is a :data:`~jsonlogic.typing.JSONLogicPrimitive`
-            or an :class:`Operator` instance.
+            An :class:`Operator` instance.
         """
         if not isinstance(self.expression, dict):
             return self.expression
 
         op_id, op_args = next(iter(self.expression.items()))
         OperatorCls = operator_registry.get(op_id)
 
-        return OperatorCls.from_expression(op_id, [op_arg.as_operator_tree(operator_registry) for op_arg in op_args])
+        return OperatorCls.from_expression(op_id, [self._as_op_impl(op_arg, operator_registry) for op_arg in op_args])

src/jsonlogic/evaluation/utils.py

@@ -57,4 +57,6 @@ def get_value(obj: OperatorArgument, context: EvaluationContext) -> Any:
     """
     if isinstance(obj, Operator):
         return obj.evaluate(context)
+    if isinstance(obj, list):
+        return [get_value(sub_obj, context) for sub_obj in obj]
     return _cast_value(obj, context.settings.literal_casts)

src/jsonlogic/typechecking/utils.py

@@ -4,7 +4,7 @@
 
 from jsonlogic.core import Operator
 from jsonlogic.json_schema import from_value
-from jsonlogic.json_schema.types import JSONSchemaType
+from jsonlogic.json_schema.types import ArrayType, JSONSchemaType, UnionType
 from jsonlogic.typing import OperatorArgument
 
 from .diagnostics import Diagnostic
@@ -44,4 +44,6 @@ def get_type(obj: OperatorArgument, context: TypecheckContext) -> JSONSchemaType
     """
     if isinstance(obj, Operator):
         return obj.typecheck(context)
+    if isinstance(obj, list):
+        return ArrayType(UnionType(*(get_type(sub_obj, context) for sub_obj in obj)))
     return from_value(obj, context.settings.literal_casts)

src/jsonlogic/typing.py

@@ -19,29 +19,31 @@
 JSONArray: TypeAlias = "list[JSON]"
 JSON: TypeAlias = "JSONPrimitive | JSONArray | JSONObject"
 
-JSONLogicPrimitive: TypeAlias = "JSONPrimitive | list[JSONPrimitive]"
-"""A JSON Logic primitive is defined as either a JSON primitive or a list of JSON primitives.
+JSONLogicPrimitive: TypeAlias = "JSONPrimitive | list[JSONLogicPrimitive]"
+"""A JSON Logic primitive is recursively defined as either a JSON primitive or a list of JSON Logic primitives.
 
 Such primitives are only considered when dealing with operator arguments:
 
-.. code-block:: javascript
+.. code-block:: json
 
     {
         "op": [
             "a string", // A valid primitive (in this case a JSON primitive)
-            ["a list"] // A list of JSON primitives
+            ["a list"], // A list of JSON primitives
+            [1, [2, 3]]
         ]
     }
 """
 
-OperatorArgument: TypeAlias = "JSONLogicPrimitive | Operator"
-"""A valid operator argument, either a JSON Logic primitive or an operator.
+OperatorArgument: TypeAlias = "Operator | JSONLogicPrimitive | list[OperatorArgument]"
+"""An operator argument is recursively defined a JSON Logic primitive, an operator or a list of operator arguments.
 
-.. code-block:: javascript
+.. code-block:: json
 
     {
         "op": [
-            {"nested_op": ...}, // A nested operator
+            {"nested_op": "..."}, // A nested operator
+            [1, {"other_op": "..."}],
             ["a list"] // A JSON Logic primitive
         ]
     }

tests/operators/test_evaluate.py

@@ -184,8 +184,7 @@ def test_map() -> None:
     assert rv == [3.0, 4.0]
 
 
-@pytest.mark.xfail(reason="Arrays are currently considered as JSON Logic primitives.")
-def test_map_op_in_values():
+def test_map_op_in_values() -> None:
     op = as_op({"map": [["2000-01-01", {"var": "/my_date"}], {">": [{"var": ""}, "1970-01-01"]}]})
 
     rv = evaluate(
@@ -198,6 +197,23 @@ def test_map_op_in_values():
     assert rv == [True, False]
 
 
+def test_nested_map() -> None:
+    op = as_op(
+        {
+            "map": [
+                [[1, 2], [3, {"var": "/my_number"}]],
+                {"var": ""},
+            ],
+        }
+    )
+
+    rv = evaluate(
+        op, data={"my_number": 4}, data_schema={"type": "object", "properties": {"my_number": {"type": "integer"}}}
+    )
+
+    assert rv == [[1, 2], [3, 4]]
+
+
 def test_map_root_reference() -> None:
     # The `/@1` reference should resolve to the "" attribute of the top level schema,
     # meaning the variables of the `map` operators are meaningless.