Expose a Transform class to build & evaluate a JSONata expression

.vscode/extensions.json

@@ -0,0 +1,9 @@
+{
+    "recommendations": [
+        "ms-python.python",
+        "ms-python.debugpy",
+        "detachhead.basedpyright",
+        "charliermarsh.ruff",
+    ],
+    "unwantedRecommendations": []
+}

.vscode/settings.json

@@ -1,7 +1,20 @@
 {
-    "python.defaultInterpreterPath": "${workspaceFolder}/.venv",
-    "python.testing.pytestEnabled": true,
-    "python.experiments.optInto": [
-        "pythonTestAdapter"
-    ],
+  "python.defaultInterpreterPath": "${workspaceFolder}/.venv",
+  "python.experiments.enabled": false,
+  "python.experiments.optInto": [
+    "pythonTestAdapter"
+  ],
+  "python.testing.pytestEnabled": true,
+  "editor.formatOnSave": true,
+  "editor.codeActionsOnSave": {
+    "source.organizeImports": "explicit"
+  },
+  "[python]": {
+    "editor.formatOnSave": true,
+    "editor.defaultFormatter": "charliermarsh.ruff",
+    "editor.codeActionsOnSave": {
+      "source.fixAll": "explicit",
+    },
+  },
+  "ruff.organizeImports": false,
 }

magicparse/__init__.py

@@ -14,7 +14,7 @@
     Builder,
     builtins as builtins_composite_processors,
 )
-from .transform import Transform
+from .transform import ParsingTransform, Transform
 from .type_converters import TypeConverter, builtins as builtins_type_converters
 from typing import Any
 from .validators import Validator, builtins as builtins_validators
@@ -30,6 +30,7 @@
     "RowParsed",
     "RowSkipped",
     "RowFailed",
+    "Transform",
     "Validator",
 ]
 
@@ -44,7 +45,7 @@ def stream_parse(data: bytes | BytesIO, schema_options: dict[str, Any]) -> Itera
     return schema_definition.stream_parse(data)
 
 
-Registrable = type[Schema] | type[Transform]
+Registrable = type[Schema] | type[ParsingTransform]
 
 
 def register(items: Registrable | Sequence[Registrable]) -> None:

magicparse/builders.py

@@ -2,10 +2,10 @@
 from decimal import Decimal
 from typing import Any, cast
 
-from .transform import Transform, OnError
+from .transform import ParsingTransform, OnError
 
 
-class Builder(Transform, ABC):
+class Builder(ParsingTransform, ABC):
     registry = dict[str, type["Builder"]]()
 
     @classmethod

magicparse/post_processors.py

@@ -1,9 +1,9 @@
-from .transform import Transform, OnError
+from .transform import ParsingTransform, OnError
 from decimal import Decimal
 from typing import Any
 
 
-class PostProcessor(Transform):
+class PostProcessor(ParsingTransform):
     registry = dict[str, type["PostProcessor"]]()
 
     @classmethod

magicparse/pre_processors.py

@@ -1,9 +1,9 @@
 import re
 from typing import Any
-from .transform import Transform, OnError
+from .transform import ParsingTransform, OnError
 
 
-class PreProcessor(Transform):
+class PreProcessor(ParsingTransform):
     registry = dict[str, type["PreProcessor"]]()
 
     @classmethod

magicparse/transform.py

@@ -2,6 +2,7 @@
 from dataclasses import dataclass
 from enum import StrEnum
 from typing import Any, Self
+from jsonata import Jsonata  # pyright: ignore[reportMissingTypeStubs]
 
 
 @dataclass(frozen=True, slots=True)
@@ -22,15 +23,15 @@ class OnError(StrEnum):
     SKIP_ROW = "skip-row"
 
 
-class Transform(ABC):
+class ParsingTransform(ABC):
     registry: dict[str, type[Self]]
 
     def __init__(self, on_error: OnError) -> None:
         self.on_error = on_error
 
     @classmethod
     @abstractmethod
-    def build(cls, options: dict[str, Any]) -> "Transform":
+    def build(cls, options: dict[str, Any]) -> "ParsingTransform":
         pass
 
     @abstractmethod
@@ -45,3 +46,9 @@ def key() -> str:
     @classmethod
     def register(cls, transform: type[Self]) -> None:
         cls.registry[transform.key()] = transform
+
+
+class Transform(Jsonata):
+    @classmethod
+    def build(cls, expression: str) -> "Transform":
+        return Transform(expr=expression)

magicparse/type_converters.py

@@ -3,11 +3,11 @@
 from decimal import Decimal
 from typing import Any, cast
 
-from .transform import Transform
+from .transform import ParsingTransform
 from .transform import OnError
 
 
-class TypeConverter(Transform):
+class TypeConverter(ParsingTransform):
     registry = dict[str, type["TypeConverter"]]()
 
     def __init__(self, nullable: bool, on_error: OnError) -> None:
@@ -28,7 +28,7 @@ def convert(self, value: str) -> Any:
         pass
 
     @classmethod
-    def build(cls, options: dict[str, Any]) -> "Transform":
+    def build(cls, options: dict[str, Any]) -> "ParsingTransform":
         try:
             type = cast(str | dict[str, Any], options["type"])
             if isinstance(type, str):

magicparse/validators.py

@@ -1,10 +1,10 @@
 from decimal import Decimal
 from typing import Any
-from .transform import Transform, OnError
+from .transform import ParsingTransform, OnError
 import re
 
 
-class Validator(Transform):
+class Validator(ParsingTransform):
     registry = dict[str, type["Validator"]]()
 
     @classmethod

pyproject.toml

@@ -9,6 +9,7 @@ repository = "https://github.com/ZeroGachis/magicparse"
 
 [tool.poetry.dependencies]
 python = "^3.13"
+jsonata-python = "^0.6.1"
 
 [tool.poetry.group.dev.dependencies]
 pytest = "^9"