diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/tests/documentation.py | 27 |
1 files changed, 12 insertions, 15 deletions
diff --git a/src/tests/documentation.py b/src/tests/documentation.py index c9f6265..28369ed 100644 --- a/src/tests/documentation.py +++ b/src/tests/documentation.py @@ -382,6 +382,9 @@ calling func with args (), {} ``` +Decorator factories +------------------------------------------- + The `decorator` function can also be used to define factories of decorators, i.e. functions returning decorators. In general you can just write something like this: @@ -394,9 +397,8 @@ def decfactory(param1, param2, ...): ``` This is fully general but requires an additional level of nesting. For this -reason since version 4.2 there is a facility to build -decorator factories by using a single caller with default arguments i.e. -writing something like this: +reason since version 4.2 there is a facility to build decorator factories by +using a single caller with default arguments i.e. writing something like this: ```python def caller(f, param1=default1, param2=default2, ..., *args, **kw): @@ -410,22 +412,17 @@ restriction, there exists an unique default decorator, i.e. the member of the family which uses the default values for all parameters. Such decorator can be written as ``decfactory()`` with no parameters specified; moreover, as a shortcut, it is also possible to elide the parenthesis, -a feature much requested by the users. For years I have been opposite -to this feature request, since having explicit parenthesis to me is more clear +a feature much requested by the users. For years I have been opposing +the request, since having explicit parenthesis to me is more clear and less magic; however once this feature entered in decorators of the Python standard library (I am referring to the [dataclass decorator]( https://www.python.org/dev/peps/pep-0557/)) I finally gave up. -The example below will show how it works in practice. - -Decorator factories -------------------------------------------- - -Sometimes one has to deal with blocking resources, such as ``stdin``. -Sometimes it is better to receive a "busy" message than just blocking -everything. -This can be accomplished with a suitable family of decorators (decorator -factory), parameterize by a string, the busy message: +The example below shows how it works in practice. The goal is to +convert a function relying on a blocking resource into a function +returning a "busy" message if the resource is not available. +This can be accomplished with a suitable family of decorators +parameterize by a string, the busy message: $$blocking |