Add inherit_docstring decorator

README.md

@@ -191,6 +191,42 @@ Notes:
 """
 ```
 
+## Using decorators
+
+Functions and methods can be decorated with the `inherit_docstring` decorator
+to inherit the docstring of another function or method. For example, the above
+example can be rewritten as:
+
+```python
+from docstring_inheritance import inherit_docstring
+
+
+def parent():
+  """Parent summary.
+
+  Args:
+      x: Description for x.
+      y: Description for y.
+
+  Notes:
+      Parent notes.
+  """
+
+
+@inherit_docstring(source=parent, style="google")
+def child():
+  """
+  Args:
+      z: Description for z.
+
+  Returns:
+      Something.
+
+  Notes:
+      Child notes.
+  """
+```
+
 # Docstring inheritance specification
 
 ## Sections order

src/docstring_inheritance/__init__.py

@@ -19,7 +19,7 @@
 # SOFTWARE.
 from __future__ import annotations
 
-from typing import Any
+from typing import Any, Callable, Literal
 
 from .class_docstrings_inheritor import ClassDocstringsInheritor
 from .class_docstrings_inheritor import DocstringInheritor
@@ -120,3 +120,16 @@ def __init__(
             inherit_numpy_docstring,
             init_in_class=True,
         )
+
+
+def inherit_docstring(func: Callable = None, *, source: Callable = None, style: Literal["numpy", "google"] = "numpy"):
+    """Decorator for inherit docstring from other functions."""
+    assert source is not None, "Source function is not given."
+    assert style in ("numpy", "google"), "Style must be either 'numpy' or 'google'."
+
+    def wrapper(f):
+        inherit_func = inherit_numpy_docstring if style == "numpy" else inherit_google_docstring
+        inherit_func(source.__doc__, f)
+        return f
+
+    return wrapper if func is None else wrapper(func)

tests/test_inheritance_for_functions.py

@@ -23,6 +23,7 @@
 
 import pytest
 
+from docstring_inheritance import inherit_docstring
 from docstring_inheritance import inherit_google_docstring
 from docstring_inheritance import inherit_numpy_docstring
 from docstring_inheritance.class_docstrings_inheritor import ClassDocstringsInheritor
@@ -131,6 +132,38 @@ def child(x, missing_doc, *child_varargs, **child_kwargs):
     assert child.__doc__ == expected.strip("\n")
 
 
+def test_decorator():
+    def parent(arg, *parent_varargs, **parent_kwargs):
+        """Parent summary.
+
+        Args:
+            arg: desc
+            *parent_varargs: Parent *args
+            **parent_kwargs: Parent **kwargs
+        """
+
+    @inherit_docstring(source=parent, style="google")
+    def child(x, missing_doc, *child_varargs, **child_kwargs):
+        """Child summary.
+
+        Args:
+            x: X
+            child_varargs: Not *args
+            *child_varargs: Child *args
+            **child_kwargs: Child **kwargs
+        """
+
+    expected = """Child summary.
+
+Args:
+    x: X
+    missing_doc: The description is missing.
+    *child_varargs: Child *args
+    **child_kwargs: Child **kwargs
+"""
+    assert child.__doc__ == expected.strip("\n")
+
+
 @pytest.mark.parametrize(
     "inherit_docstring", [inherit_numpy_docstring, inherit_google_docstring]
 )