fix: filter context selector from filter function, closes #8

Author: jg-rp

jsonpath/parse.py

@@ -243,6 +243,7 @@ def __init__(self, *, env: JSONPathEnvironment) -> None:
             TOKEN_TRUE: self.parse_boolean,
             TOKEN_ROOT: self.parse_root_path,
             TOKEN_SELF: self.parse_self_path,
+            TOKEN_FILTER_CONTEXT: self.parse_filter_context_path,
         }
 
     def parse(self, stream: TokenStream) -> Iterable[JSONPathSelector]:

tests/test_filter_context.py

@@ -0,0 +1,19 @@
+"""Extra filter context test cases."""
+import pytest
+
+from jsonpath import JSONPathEnvironment
+
+
+@pytest.fixture()
+def env() -> JSONPathEnvironment:
+    return JSONPathEnvironment()
+
+
+def test_filter_context_selector_in_filter_function(env: JSONPathEnvironment) -> None:
+    """Test that we can pass extra filter context to findall."""
+    rv = env.findall(
+        "$[?(@.some == length(_.other))]",
+        {"foo": {"some": 1, "thing": 2}},
+        filter_context={"other": ["a"]},
+    )
+    assert rv == [{"some": 1, "thing": 2}]