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authorMichele Simionato <michele.simionato@gmail.com>2018-01-14 07:34:06 +0100
committerMichele Simionato <michele.simionato@gmail.com>2018-01-14 07:34:06 +0100
commit19d0c29e7eda192da4ecb0210fb67d0c84a39415 (patch)
tree00db850931c821275f3aaa4596dcbb41bcd3ce3c /docs
parent532347c0d4523ac79025ae1255a0e4ac0b84c3fe (diff)
downloadpython-decorator-git-19d0c29e7eda192da4ecb0210fb67d0c84a39415.tar.gz
Regenerated the docs
Diffstat (limited to 'docs')
-rw-r--r--docs/tests.documentation.rst82
1 files changed, 61 insertions, 21 deletions
diff --git a/docs/tests.documentation.rst b/docs/tests.documentation.rst
index f77cb10..df04e7c 100644
--- a/docs/tests.documentation.rst
+++ b/docs/tests.documentation.rst
@@ -3,7 +3,7 @@ The ``decorator`` module
:Author: Michele Simionato
:E-mail: michele.simionato@gmail.com
-:Version: 4.1.2 (2017-07-23)
+:Version: 4.1.2 (2018-01-14)
:Supports: Python 2.6, 2.7, 3.0, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6
:Download page: http://pypi.python.org/pypi/decorator/4.1.2
:Installation: ``pip install decorator``
@@ -39,9 +39,9 @@ What's New in version 4
- **New documentation**
There is now a single manual for all Python versions, so I took the
- opportunity to overhaul the documentation. So, even if you are
- a long-time user, you may want to revisit the docs, since several
- examples have been improved.
+ opportunity to overhaul the documentation and to move it to readthedocs.org.
+ Even if you are a long-time user, you may want to revisit the docs, since
+ several examples have been improved.
- **Packaging improvements**
The code is now also available in wheel format. Integration with
@@ -72,6 +72,11 @@ What's New in version 4
defined with the `async def` syntax, and to maintain the
`inspect.iscoroutinefunction` check working for the decorated function.
+- **Decorator factories**
+
+ From version 4.2 there is facility to define factories of decorators in
+ a simple way, a feature requested by the users since a long time.
+
Usefulness of decorators
------------------------------------------------
@@ -465,31 +470,66 @@ Here is an example of usage:
>>> func()
calling func with args (), {}
+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:
+
+.. code-block:: python
+
+ def decfactory(param1, param2, ...):
+ def caller(f, *args, **kw):
+ return somefunc(f, param1, param2, .., *args, **kw)
+ return decorator(caller)
+
+This is fully general but requires an additional level of nesting. For this
+reasone 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:
+
+.. code-block:: python
+
+ def caller(f, param1=default1, param2=default2, ..., *args, **kw):
+ return somefunc(f, param1, param2, *args, **kw)
+ decfactory = decorator(caller)
+
+Notice that this simplified approach *only works with default arguments*,
+i.e. `param1`, `param2` etc must have known defaults. Thanks to this
+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 expliciti 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.
+
``blocking``
-------------------------------------------
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,
-where the parameter is the busy message:
+This can be accomplished with a suitable family of decorators (decorator
+factory), parameterize by a string, the busy message:
.. code-block:: python
- def blocking(not_avail):
- def _blocking(f, *args, **kw):
- if not hasattr(f, "thread"): # no thread running
- def set_result():
- f.result = f(*args, **kw)
- f.thread = threading.Thread(None, set_result)
- f.thread.start()
- return not_avail
- elif f.thread.isAlive():
- return not_avail
- else: # the thread is ended, return the stored result
- del f.thread
- return f.result
- return decorator(_blocking)
+ @decorator
+ def blocking(f, msg='blocking', *args, **kw):
+ if not hasattr(f, "thread"): # no thread running
+ def set_result():
+ f.result = f(*args, **kw)
+ f.thread = threading.Thread(None, set_result)
+ f.thread.start()
+ return msg
+ elif f.thread.isAlive():
+ return msg
+ else: # the thread is ended, return the stored result
+ del f.thread
+ return f.result
Functions decorated with ``blocking`` will return a busy message if
@@ -498,7 +538,7 @@ available. For instance:
.. code-block:: python
- >>> @blocking("Please wait ...")
+ >>> @blocking(msg="Please wait ...")
... def read_data():
... time.sleep(3) # simulate a blocking resource
... return "some data"