📝 Write and configure documentation

docs/api_reference/decorators.md

@@ -0,0 +1 @@
+::: marshmallow_generic.decorators

docs/api_reference/schema.md

@@ -0,0 +1 @@
+::: marshmallow_generic.schema

docs/index.md

@@ -1,15 +1,82 @@
 # marshmallow-generic
 
-Generic schema with full typing support and minimal boilerplate
+**Generic schema with full typing support and minimal boilerplate**
 
-## Usage
+---
+
+**Documentation**: <a href="http://daniil-berg.github.io/marshmallow-generic" target="_blank"> daniil-berg.github.io/marshmallow-generic </a>
+
+**Source Code**: <a href="https://github.com/daniil-berg/marshmallow-generic" target="_blank"> github.com/daniil-berg/marshmallow-generic </a>
+
+---
+
+Extension for <a href="https://github.com/marshmallow-code/marshmallow" target="_blank">`marshmallow`</a> to make <a href="https://marshmallow.readthedocs.io/en/stable/quickstart.html#deserializing-to-objects" target="_blank">deserialization to objects</a> easier and improve type safety.
+
+The main `GenericSchema` class extends <a href="https://marshmallow.readthedocs.io/en/stable/marshmallow.schema.html#marshmallow.schema.Schema" target="_blank">`marshmallow.Schema`</a> making it **generic** in terms of the class that data should be deserialized to, when calling <a href="https://marshmallow.readthedocs.io/en/stable/marshmallow.schema.html#marshmallow.schema.Schema.load" target="_blank">`load`/`loads`</a>.
+
+With `GenericSchema` there is no need to explicitly write `post_load` hooks to initialize the object anymore. 🎉
+
+If the "model" class is (for example) `User`, it just needs to be passed as the type argument, when subclassing `GenericSchema`. Depending on whether `many` is `True` or not, the output of the `load`/`loads` method will then be automatically inferred as either `User` or `list[User]` by any competent type checker. ✨
+
+## Usage Example
+
+```python
+from marshmallow import fields
+from marshmallow_generic import GenericSchema
+
+
+class User:
+    def __init__(self, name: str, email: str) -> None:
+        self.name = name
+        self.email = email
+
+    def __repr__(self) -> str:
+        return "<User(name={self.name!r})>".format(self=self)
 
 ...
 
+class UserSchema(GenericSchema[User]):
+    name = fields.Str()
+    email = fields.Email()
+
+
+user_data = {"name": "Monty", "email": "monty@python.org"}
+schema = UserSchema()
+single_user = schema.load(user_data)
+print(single_user)  # <User(name='Monty')>
+
+json_data = '''[
+    {"name": "Monty", "email": "monty@python.org"},
+    {"name": "Ronnie", "email": "ronnie@stones.com"}
+]'''
+multiple_users = schema.loads(json_data, many=True)
+print(multiple_users)  # [<User(name='Monty')>, <User(name='Ronnie')>]
+```
+
+Adding `reveal_type(single_user)` and `reveal_type(multiple_users)` at the bottom and running that code through <a href="https://mypy.readthedocs.io/en/stable/" target="_blank">`mypy`</a> would yield the following output:
+
+```
+# note: Revealed type is "User"
+# note: Revealed type is "builtins.list[User]"
+```
+
+With the regular `marshmallow.Schema`, the output of `mypy` would instead be this:
+
+```
+# note: Revealed type is "Any"
+# note: Revealed type is "Any"
+```
+
+This also means your IDE will be able to infer the types and thus provide useful auto-suggestions for the loaded objects. 👨‍💻
+
+Here is PyCharm with the example from above:
+
+![Image title](img/ide_suggestion_user.png){ width="540" }
+
 ## Installation
 
 `pip install marshmallow-generic`
 
 ## Dependencies
 
-Python Version ..., OS ...
+Python Version `3.9+` and `marshmallow` (duh)

mkdocs.yaml

@@ -26,13 +26,28 @@ extra_css:
 
 plugins:
   - search
-  - mkdocstrings
+  - mkdocstrings:
+      handlers:
+        python:
+          options:
+            show_source: false
+            show_root_toc_entry: false
+          import:
+            - https://marshmallow.readthedocs.io/en/stable/objects.inv
 
 markdown_extensions:
   - admonition
   - codehilite
   - extra
   - pymdownx.superfences
+  - toc:
+      permalink: true
+
+watch:
+  - src
 
 nav:
   - Home: index.md
+  - 'API Reference':
+    - api_reference/schema.md
+    - api_reference/decorators.md

pyproject.toml

@@ -120,6 +120,7 @@ ignore = [
     "D203", # 1 blank line required before class docstring -> D211 is better
     "D212", # Multi-line docstring summary should start at the first line -> ugly, D212 is better
     "D401", # First line of docstring should be in imperative mood -> no, it shouldn't
+    "D407", # Missing dashed underline after section -> different docstring style
 ]
 
 [tool.ruff.per-file-ignores]

src/marshmallow_generic/decorators.py

@@ -1,4 +1,8 @@
-"""Typed overloads for some of the `marshmallow.decorators` module."""
+"""
+Typed overloads for the [`marshmallow.decorators`][marshmallow.decorators] module.
+
+Implements decorators as generic in terms of the decorated method types.
+"""
 
 from collections.abc import Callable
 from typing import Any, Optional, TypeVar, overload
@@ -34,9 +38,31 @@ def post_load(
     pass_original: bool = False,
 ) -> Callable[..., Any]:
     """
-    Typed overload of the original `marshmallow.post_load` decorator function.
+    Register a method to invoke after deserializing an object.
 
+    Typed overload of the original [`marshmallow.post_load`]
+    [marshmallow.post_load] decorator function.
     Generic to ensure that the decorated function retains its type.
     Runtime behavior is unchanged.
+
+    Receives the deserialized data and returns the processed data.
+    By default it receives a single object at a time, transparently handling
+    the `many` argument passed to the [`Schema.load`][marshmallow.Schema.load]
+    call.
+
+    Args:
+        fn (Optional[Callable[P, R]]):
+            The function to decorate or `None`; if a function is supplied,
+            a decorated version of it is returned; if `None` the decorator
+            is returned with its other arguments already bound.
+        pass_many:
+            If `True`, the raw data (which may be a collection) is passed
+        pass_original:
+            If `True`, the original data (before deserializing) will be passed
+            as an additional argument to the method
+
+    Returns:
+        (Callable[P, R]): if `fn` is passed a function
+        (Callable[[Callable[P, R]], Callable[P, R]]): if `fn` is `None`
     """
     return _post_load(fn, pass_many=pass_many, pass_original=pass_original)

src/marshmallow_generic/schema.py

@@ -1,4 +1,9 @@
-"""Definition of the `GenericSchema` base class."""
+"""
+Definition of the `GenericSchema` base class.
+
+For details about the inherited methods and attributes, see the official
+documentation of [`marshmallow.Schema`][marshmallow.Schema].
+"""
 
 from collections.abc import Iterable, Mapping, Sequence
 from typing import TYPE_CHECKING, Any, Literal, Optional, TypeVar, Union, overload
@@ -8,23 +13,58 @@ from marshmallow import Schema
 from ._util import GenericInsightMixin
 from .decorators import post_load
 
-_T = TypeVar("_T")
+Model = TypeVar("Model")
 
 
-class GenericSchema(GenericInsightMixin[_T], Schema):
+class GenericSchema(GenericInsightMixin[Model], Schema):
     """
-    Schema parameterized by the class it deserializes data to.
+    Generic schema parameterized by a **`Model`** class.
+
+    Data will always be deserialized to instances of that **`Model`** class.
+
+    !!! note
+        The **`Model`** referred to throughout the documentation is a
+        **type variable**, not any concrete class. For more information about
+        type variables, see the "Generics" section in
+        [PEP 484](https://peps.python.org/pep-0484/#generics).
 
     Registers a `post_load` hook to pass validated data to the constructor
-    of the specified class.
+    of the specified **`Model`**.
 
-    Requires a specific (non-generic) class to be passed as the type argument
+    Requires a specific (non-generic) class to be passed as the **`Model`**
-    for deserialization to work properly.
+    type argument for deserialization to work properly:
+
+    ```python
+    class Foo:  # Model
+        ...
+
+    class FooSchema(GenericSchema[Foo]):
+        ...
+    ```
     """
 
     @post_load
-    def instantiate(self, data: dict[str, Any], **_kwargs: Any) -> _T:
+    def instantiate(self, data: dict[str, Any], **_kwargs: Any) -> Model:
-        """Unpacks `data` into the constructor of the specified type."""
+        """
+        Unpacks `data` into the constructor of the specified **`Model`**.
+
+        Registered as a [`@post_load`]
+        [marshmallow_generic.decorators.post_load] hook for the schema.
+
+        !!! warning
+            You should probably **not** use this method directly;
+            no parsing, transformation or validation of any kind is done
+            in this method. The `data` passed to the **`Model`** constructor
+            "as is".
+
+        Args:
+            data:
+                The validated data after deserialization; will be unpacked
+                into the constructor of the specified **`Model`** class.
+
+        Returns:
+            Instance of the schema's **`Model`** initialized with `**data`
+        """
         return self._get_type_arg()(**data)
 
     if TYPE_CHECKING:
@@ -37,7 +77,7 @@ class GenericSchema(GenericInsightMixin[_T], Schema):
             many: Literal[True],
             partial: Union[bool, Sequence[str], set[str], None] = None,
             unknown: Optional[str] = None,
-        ) -> list[_T]:
+        ) -> list[Model]:
             ...
 
         @overload
@@ -48,7 +88,7 @@ class GenericSchema(GenericInsightMixin[_T], Schema):
             many: Optional[Literal[False]] = None,
             partial: Union[bool, Sequence[str], set[str], None] = None,
             unknown: Optional[str] = None,
-        ) -> _T:
+        ) -> Model:
             ...
 
         def load(
@@ -58,12 +98,40 @@ class GenericSchema(GenericInsightMixin[_T], Schema):
             many: Optional[bool] = None,
             partial: Union[bool, Sequence[str], set[str], None] = None,
             unknown: Optional[str] = None,
-        ) -> Union[list[_T], _T]:
+        ) -> Union[list[Model], Model]:
             """
-            Same as `marshmallow.Schema.load` at runtime.
+            Deserializes data to objects of the specified **`Model`** class.
+
+            Same as [`marshmallow.Schema.load`]
+            [marshmallow.schema.Schema.load] at runtime, but data will always
+            pass through the [`instantiate`]
+            [marshmallow_generic.schema.GenericSchema.instantiate]
+            hook after deserialization.
 
             Annotations ensure that type checkers will infer the return type
-            correctly based on the type argument passed to a specific subclass.
+            correctly based on the **`Model`** type argument of the class.
+
+            Args:
+                data:
+                    The data to deserialize
+                many:
+                    Whether to deserialize `data` as a collection. If `None`,
+                    the value for `self.many` is used.
+                partial:
+                    Whether to ignore missing fields and not require any
+                    fields declared. Propagates down to [`Nested`]
+                    [marshmallow.fields.Nested] fields as well. If its value
+                    is an iterable, only missing fields listed in that
+                    iterable will be ignored. Use dot delimiters to specify
+                    nested fields.
+                unknown:
+                    Whether to exclude, include, or raise an error for unknown
+                    fields in the data. Use `EXCLUDE`, `INCLUDE` or `RAISE`.
+                    If `None`, the value for `self.unknown` is used.
+
+            Returns:
+                (Model): if `many` is set to `False`
+                (list[Model]): if `many` is set to `True`
             """
             ...
 
@@ -76,7 +144,7 @@ class GenericSchema(GenericInsightMixin[_T], Schema):
             partial: Union[bool, Sequence[str], set[str], None] = None,
             unknown: Optional[str] = None,
             **kwargs: Any,
-        ) -> list[_T]:
+        ) -> list[Model]:
             ...
 
         @overload
@@ -88,7 +156,7 @@ class GenericSchema(GenericInsightMixin[_T], Schema):
             partial: Union[bool, Sequence[str], set[str], None] = None,
             unknown: Optional[str] = None,
             **kwargs: Any,
-        ) -> _T:
+        ) -> Model:
             ...
 
         def loads(
@@ -99,11 +167,41 @@ class GenericSchema(GenericInsightMixin[_T], Schema):
             partial: Union[bool, Sequence[str], set[str], None] = None,
             unknown: Optional[str] = None,
             **kwargs: Any,
-        ) -> Union[list[_T], _T]:
+        ) -> Union[list[Model], Model]:
             """
-            Same as `marshmallow.Schema.loads` at runtime.
+            Deserializes data to objects of the specified **`Model`** class.
+
+            Same as [`marshmallow.Schema.loads`]
+            [marshmallow.schema.Schema.loads] at runtime, but data will always
+            pass through the [`instantiate`]
+            [marshmallow_generic.schema.GenericSchema.instantiate]
+            hook after deserialization.
 
             Annotations ensure that type checkers will infer the return type
-            correctly based on the type argument passed to a specific subclass.
+            correctly based on the **`Model`** type argument of the class.
+
+            Args:
+                json_data:
+                    A JSON string of the data to deserialize
+                many:
+                    Whether to deserialize `data` as a collection. If `None`,
+                    the value for `self.many` is used.
+                partial:
+                    Whether to ignore missing fields and not require any
+                    fields declared. Propagates down to [`Nested`]
+                    [marshmallow.fields.Nested] fields as well. If its value
+                    is an iterable, only missing fields listed in that
+                    iterable will be ignored. Use dot delimiters to specify
+                    nested fields.
+                unknown:
+                    Whether to exclude, include, or raise an error for unknown
+                    fields in the data. Use `EXCLUDE`, `INCLUDE` or `RAISE`.
+                    If `None`, the value for `self.unknown` is used.
+                **kwargs:
+                    Passed to the JSON decoder
+
+            Returns:
+                (Model): if `many` is set to `False`
+                (list[Model]): if `many` is set to `True`
             """
             ...