diff options
Diffstat (limited to 'Doc/library')
| -rw-r--r-- | Doc/library/functools.rst | 28 |
1 files changed, 21 insertions, 7 deletions
diff --git a/Doc/library/functools.rst b/Doc/library/functools.rst index 28062c1..a81e819 100644 --- a/Doc/library/functools.rst +++ b/Doc/library/functools.rst @@ -281,23 +281,34 @@ The :mod:`functools` module defines the following functions: ... print(arg) To add overloaded implementations to the function, use the :func:`register` - attribute of the generic function. It is a decorator, taking a type - parameter and decorating a function implementing the operation for that - type:: + attribute of the generic function. It is a decorator. For functions + annotated with types, the decorator will infer the type of the first + argument automatically:: - >>> @fun.register(int) - ... def _(arg, verbose=False): + >>> @fun.register + ... def _(arg: int, verbose=False): ... if verbose: ... print("Strength in numbers, eh?", end=" ") ... print(arg) ... - >>> @fun.register(list) - ... def _(arg, verbose=False): + >>> @fun.register + ... def _(arg: list, verbose=False): ... if verbose: ... print("Enumerate this:") ... for i, elem in enumerate(arg): ... print(i, elem) + For code which doesn't use type annotations, the appropriate type + argument can be passed explicitly to the decorator itself:: + + >>> @fun.register(complex) + ... def _(arg, verbose=False): + ... if verbose: + ... print("Better than complicated.", end=" ") + ... print(arg.real, arg.imag) + ... + + To enable registering lambdas and pre-existing functions, the :func:`register` attribute can be used in a functional form:: @@ -368,6 +379,9 @@ The :mod:`functools` module defines the following functions: .. versionadded:: 3.4 + .. versionchanged:: 3.7 + The :func:`register` attribute supports using type annotations. + .. function:: update_wrapper(wrapper, wrapped, assigned=WRAPPER_ASSIGNMENTS, updated=WRAPPER_UPDATES) |