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Merge pull request #12389 from ftobia/patch-1...
Matthias Bussonnier -
r25837:3def17fa merge
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@@ -8,7 +8,7 b' Asynchronous in REPL: Autoawait'
8 8 This feature is experimental and behavior can change between python and
9 9 IPython version without prior deprecation.
10 10
11 Starting with IPython 7.0, and when user Python 3.6 and above, IPython offer the
11 Starting with IPython 7.0, and when using Python 3.6 and above, IPython offer the
12 12 ability to run asynchronous code from the REPL. Constructs which are
13 13 :exc:`SyntaxError` s in the Python REPL can be used seamlessly in IPython.
14 14
@@ -19,7 +19,7 b' will differ between IPython, IPykernel and their versions.'
19 19
20 20 When a supported library is used, IPython will automatically allow Futures and
21 21 Coroutines in the REPL to be ``await`` ed. This will happen if an :ref:`await
22 <await>` (or any other async constructs like async-with, async-for) is use at
22 <await>` (or any other async constructs like async-with, async-for) is used at
23 23 top level scope, or if any structure valid only in `async def
24 24 <https://docs.python.org/3/reference/compound_stmts.html#async-def>`_ function
25 25 context are present. For example, the following being a syntax error in the
@@ -73,7 +73,7 b" By default IPython will assume integration with Python's provided"
73 73 :mod:`asyncio`, but integration with other libraries is provided. In particular
74 74 we provide experimental integration with the ``curio`` and ``trio`` library.
75 75
76 You can switch current integration by using the
76 You can switch the current integration by using the
77 77 ``c.InteractiveShell.loop_runner`` option or the ``autoawait <name
78 78 integration>`` magic.
79 79
@@ -118,7 +118,7 b' to your code.'
118 118
119 119 When using command line IPython, the default loop (or runner) does not process
120 120 in the background, so top level asynchronous code must finish for the REPL to
121 allow you to enter more code. As with usual Python semantic, the awaitables are
121 allow you to enter more code. As with usual Python semantics, the awaitables are
122 122 started only when awaited for the first time. That is to say, in first example,
123 123 no network request is done between ``In[1]`` and ``In[2]``.
124 124
@@ -131,8 +131,8 b' a loop to run. By default IPython will use a fake coroutine runner which should'
131 131 allow ``IPython.embed()`` to be nested. Though this will prevent usage of the
132 132 :magic:`%autoawait` feature when using IPython embed.
133 133
134 You can set explicitly a coroutine runner for ``embed()`` if you desire to run
135 asynchronous code, the exact behavior is though undefined.
134 You can set a coroutine runner explicitly for ``embed()`` if you want to run
135 asynchronous code, though the exact behavior is undefined.
136 136
137 137 Effects on Magics
138 138 -----------------
@@ -140,14 +140,14 b' Effects on Magics'
140 140 A couple of magics (``%%timeit``, ``%timeit``, ``%%time``, ``%%prun``) have not
141 141 yet been updated to work with asynchronous code and will raise syntax errors
142 142 when trying to use top-level ``await``. We welcome any contribution to help fix
143 those, and extra cases we haven't caught yet. We hope for better support in Cor
143 those, and extra cases we haven't caught yet. We hope for better support in Core
144 144 Python for top-level Async code.
145 145
146 146 Internals
147 147 ---------
148 148
149 149 As running asynchronous code is not supported in interactive REPL (as of Python
150 3.7) we have to rely to a number of complex workaround and heuristic to allow
150 3.7) we have to rely to a number of complex workarounds and heuristics to allow
151 151 this to happen. It is interesting to understand how this works in order to
152 152 comprehend potential bugs, or provide a custom runner.
153 153
@@ -179,16 +179,16 b' significant overhead to this kind of code.'
179 179 By default the generated coroutine function will be consumed by Asyncio's
180 180 ``loop_runner = asyncio.get_evenloop().run_until_complete()`` method if
181 181 ``async`` mode is deemed necessary, otherwise the coroutine will just be
182 exhausted in a simple runner. It is though possible to change the default
182 exhausted in a simple runner. It is possible, though, to change the default
183 183 runner.
184 184
185 185 A loop runner is a *synchronous* function responsible from running a coroutine
186 186 object.
187 187
188 The runner is responsible from ensuring that ``coroutine`` run to completion,
189 and should return the result of executing the coroutine. Let's write a
188 The runner is responsible for ensuring that ``coroutine`` runs to completion,
189 and it should return the result of executing the coroutine. Let's write a
190 190 runner for ``trio`` that print a message when used as an exercise, ``trio`` is
191 special as it usually prefer to run a function object and make a coroutine by
191 special as it usually prefers to run a function object and make a coroutine by
192 192 itself, we can get around this limitation by wrapping it in an async-def without
193 193 parameters and passing this value to ``trio``::
194 194
@@ -246,8 +246,8 b' Difference between terminal IPython and IPykernel'
246 246 The exact asynchronous code running behavior varies between Terminal IPython and
247 247 IPykernel. The root cause of this behavior is due to IPykernel having a
248 248 *persistent* `asyncio` loop running, while Terminal IPython starts and stops a
249 loop for each code block. This can lead to surprising behavior in some case if
250 you are used to manipulate asyncio loop yourself, see for example
249 loop for each code block. This can lead to surprising behavior in some cases if
250 you are used to manipulating asyncio loop yourself, see for example
251 251 :ghissue:`11303` for a longer discussion but here are some of the astonishing
252 252 cases.
253 253
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