Generic transforms

pyproject.toml

@@ -1,6 +1,6 @@
 [project]
 name = "dataglasses"
-version = "0.6.0"
+version = "0.7.0"
 dependencies = []
 requires-python = ">=3.10"
 authors = [{ name = "Uri Granta", email = "uri.granta+python@gmail.com" }]

src/dataglasses/core.py

@@ -105,7 +105,11 @@ def _from_dict(
                 datacls,
             )
 
-        origin = get_origin(cls)
+        origin = cast(type, get_origin(cls))
+
+        if origin in transform and not transformed:
+            input_type, fn = transform[origin]
+            return fn(_from_dict(input_type, value, datacls, transformed=True))
 
         if origin in (collections.abc.Sequence, list):
             if not isinstance(value, Sequence):
@@ -274,7 +278,11 @@ def _json_schema(
             evaluated_type = cast(type, ref._evaluate(_globals, _locals, frozenset()))
             return _json_schema(evaluated_type, datacls)
 
-        origin = get_origin(cls)
+        origin = cast(type, get_origin(cls))
+
+        if origin in transform and not transformed:
+            input_type, _ = transform[origin]
+            return _json_schema(input_type, datacls, transformed=True)
 
         if origin in (collections.abc.Sequence, list):
             sequence_type = get_args(cls)[0]

tests/test_dataklasses.py

@@ -446,6 +446,25 @@ def test_transform(transform: TransformRules, output: DataclassTransform) -> Non
     validate(value, schema)
 
 
+@dataclass
+class DataclassTransformGeneric:
+    a: set[str]
+    b: set[int]
+    c: set[float]
+
+
+def test_transform_generic() -> None:
+    value = {"a": ["a", "b"], "b": [1, 2], "c": [0.5, 0.7]}
+    transform: TransformRules = {
+        set: (list[str | int], set),
+        set[float]: (list[float], lambda lst: set(lst) | {0.0}),
+    }
+    data = from_dict(DataclassTransformGeneric, value, transform=transform)
+    assert data == DataclassTransformGeneric({"a", "b"}, {1, 2}, {0.0, 0.5, 0.7})
+    schema = to_json_schema(DataclassTransformGeneric, transform=transform)
+    validate(value, schema)
+
+
 # =================
 # UNSUPPORTED TYPES
 # =================