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@@ -1,95 +1,96 b'' | |||
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1 | 1 | """ |
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2 | 2 | Async helper function that are invalid syntax on Python 3.5 and below. |
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3 | 3 | |
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4 | 4 | Known limitation and possible improvement. |
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5 | 5 | |
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6 | 6 | Top level code that contain a return statement (instead of, or in addition to |
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7 | 7 | await) will be detected as requiring being wrapped in async calls. This should |
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8 | 8 | be prevented as early return will not work. |
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9 | 9 | """ |
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10 | 10 | |
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11 | 11 | |
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12 | 12 | import ast |
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13 | 13 | import sys |
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14 | 14 | import inspect |
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15 | 15 | from textwrap import dedent, indent |
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16 | 16 | from types import CodeType |
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17 | 17 | |
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18 | 18 | |
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19 | 19 | def _asyncio_runner(coro): |
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20 | 20 | """ |
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21 | 21 | Handler for asyncio autoawait |
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22 | 22 | """ |
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23 | 23 | import asyncio |
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24 | 24 | |
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25 | 25 | return asyncio.get_event_loop().run_until_complete(coro) |
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26 | 26 | |
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27 | 27 | |
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28 | 28 | def _curio_runner(coroutine): |
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29 | 29 | """ |
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30 | 30 | handler for curio autoawait |
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31 | 31 | """ |
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32 | 32 | import curio |
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33 | 33 | |
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34 | 34 | return curio.run(coroutine) |
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35 | 35 | |
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36 | 36 | |
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37 | 37 | if sys.version_info > (3, 5): |
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38 | 38 | # nose refuses to avoid this file and async def is invalidsyntax |
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39 | 39 | s = dedent( |
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40 | 40 | ''' |
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41 | 41 | def _trio_runner(function): |
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42 | 42 | import trio |
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43 | 43 | async def loc(coro): |
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44 | 44 | """ |
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45 | 45 | We need the dummy no-op async def to protect from |
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46 | 46 | trio's internal. See https://github.com/python-trio/trio/issues/89 |
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47 | 47 | """ |
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48 | 48 | return await coro |
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49 | 49 | return trio.run(loc, function) |
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50 | 50 | ''' |
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51 | 51 | ) |
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52 | 52 | exec(s, globals(), locals()) |
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53 | 53 | |
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54 | 54 | |
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55 | 55 | def _asyncify(code: str) -> str: |
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56 | 56 | """wrap code in async def definition. |
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57 | 57 | |
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58 | 58 | And setup a bit of context to run it later. |
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59 | 59 | """ |
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60 | 60 | res = dedent( |
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61 | 61 | """ |
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62 | 62 | async def __wrapper__(): |
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63 | 63 | try: |
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64 | 64 | {usercode} |
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65 | 65 | finally: |
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66 | 66 | locals() |
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67 | 67 | """ |
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68 | 68 | ).format(usercode=indent(code, " " * 8)[8:]) |
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69 | 69 | return res |
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70 | 70 | |
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71 | 71 | |
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72 | 72 | def _should_be_async(cell: str) -> bool: |
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73 | 73 | """Detect if a block of code need to be wrapped in an `async def` |
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74 | 74 | |
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75 | 75 | Attempt to parse the block of code, it it compile we're fine. |
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76 | 76 | Otherwise we wrap if and try to compile. |
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77 | 77 | |
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78 | 78 | If it works, assume it should be async. Otherwise Return False. |
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79 | 79 | |
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80 | 80 | Not handled yet: If the block of code has a return statement as the top |
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81 | 81 | level, it will be seen as async. This is a know limitation. |
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82 | 82 | """ |
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83 | 83 | |
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84 | 84 | try: |
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85 | 85 | # we can't limit ourself to ast.parse, as it __accepts__ to parse on |
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86 | 86 | # 3.7+, but just does not _compile_ |
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87 | 87 | compile(cell, "<>", "exec") |
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88 | 88 | return False |
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89 | 89 | except SyntaxError: |
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90 | 90 | try: |
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91 | 91 | ast.parse(_asyncify(cell)) |
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92 | # TODO verify ast has not "top level" return or yield. | |
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92 | 93 | except SyntaxError: |
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93 | 94 | return False |
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94 | 95 | return True |
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95 | 96 | return False |
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1 | NO CONTENT: modified file |
@@ -1,31 +1,27 b'' | |||
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1 | 1 | build: false |
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2 | 2 | matrix: |
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3 | 3 | fast_finish: true # immediately finish build once one of the jobs fails. |
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4 | 4 | |
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5 | 5 | environment: |
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6 | 6 | matrix: |
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7 | 7 | - PYTHON: "C:\\Python36" |
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8 | 8 | PYTHON_VERSION: "3.6.x" |
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9 | 9 | PYTHON_ARCH: "32" |
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10 | 10 | |
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11 | - PYTHON: "C:\\Python34-x64" | |
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12 | PYTHON_VERSION: "3.4.x" | |
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13 | PYTHON_ARCH: "64" | |
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14 | ||
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15 | 11 | - PYTHON: "C:\\Python36-x64" |
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16 | 12 | PYTHON_VERSION: "3.6.x" |
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17 | 13 | PYTHON_ARCH: "64" |
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18 | 14 | |
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19 | 15 | init: |
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20 | 16 | - "ECHO %PYTHON% %PYTHON_VERSION% %PYTHON_ARCH%" |
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21 | 17 | |
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22 | 18 | install: |
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23 | 19 | - "SET PATH=%PYTHON%;%PYTHON%\\Scripts;%PATH%" |
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24 | 20 | - "%CMD_IN_ENV% python -m pip install --upgrade setuptools pip" |
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25 | 21 | - "%CMD_IN_ENV% pip install nose coverage" |
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26 | 22 | - "%CMD_IN_ENV% pip install .[test]" |
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27 | 23 | - "%CMD_IN_ENV% mkdir results" |
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28 | 24 | - "%CMD_IN_ENV% cd results" |
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29 | 25 | test_script: |
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30 | 26 | - "%CMD_IN_ENV% iptest --coverage xml" |
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31 | 27 |
@@ -1,185 +1,193 b'' | |||
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1 | 1 | .. _autoawait: |
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2 | 2 | |
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3 | 3 | Asynchronous in REPL: Autoawait |
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4 | 4 | =============================== |
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5 | 5 | |
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6 |
Starting with IPython |
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7 |
ability to run asynchronous code from the REPL. |
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6 | Starting with IPython 7.0, and when user Python 3.6 and above, IPython offer the | |
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7 | ability to run asynchronous code from the REPL. Constructs which are | |
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8 | 8 | :exc:`SyntaxError` s in the Python REPL can be used seamlessly in IPython. |
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9 | 9 | |
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10 | When a supported libray is used, IPython will automatically `await` Futures | |
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11 | and Coroutines in the REPL. This will happen if an :ref:`await <await>` (or `async`) is | |
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10 | The example given here are for terminal IPython, running async code in a | |
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11 | notebook interface or any other frontend using the Jupyter protocol will need to | |
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12 | use a newer version of IPykernel. The details of how async code runs in | |
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13 | IPykernel will differ between IPython, IPykernel and their versions. | |
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14 | ||
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15 | When a supported library is used, IPython will automatically `await` Futures | |
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16 | and Coroutines in the REPL. This will happen if an :ref:`await <await>` is | |
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12 | 17 | use at top level scope, or if any structure valid only in `async def |
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13 | 18 | <https://docs.python.org/3/reference/compound_stmts.html#async-def>`_ function |
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14 | 19 | context are present. For example, the following being a syntax error in the |
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15 | 20 | Python REPL:: |
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16 | 21 | |
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17 | 22 | Python 3.6.0 |
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18 | 23 | [GCC 4.2.1] |
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19 | 24 | Type "help", "copyright", "credits" or "license" for more information. |
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20 | 25 | >>> import aiohttp |
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21 | 26 | >>> result = aiohttp.get('https://api.github.com') |
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22 | 27 | >>> response = await result |
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23 | 28 | File "<stdin>", line 1 |
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24 | 29 | response = await result |
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25 | 30 | ^ |
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26 | 31 | SyntaxError: invalid syntax |
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27 | 32 | |
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28 | 33 | Should behave as expected in the IPython REPL:: |
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29 | 34 | |
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30 | 35 | Python 3.6.0 |
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31 | 36 | Type 'copyright', 'credits' or 'license' for more information |
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32 |
IPython |
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37 | IPython 7.0.0 -- An enhanced Interactive Python. Type '?' for help. | |
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33 | 38 | |
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34 | 39 | In [1]: import aiohttp |
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35 | 40 | ...: result = aiohttp.get('https://api.github.com') |
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36 | 41 | |
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37 | 42 | In [2]: response = await result |
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38 | 43 | <pause for a few 100s ms> |
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39 | 44 | |
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40 | 45 | In [3]: await response.json() |
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41 | 46 | Out[3]: |
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42 | 47 | {'authorizations_url': 'https://api.github.com/authorizations', |
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43 | 48 | 'code_search_url': 'https://api.github.com/search/code?q={query}...', |
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44 | 49 | ... |
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45 | 50 | } |
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46 | 51 | |
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47 | 52 | |
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48 | 53 | You can use the ``c.InteractiveShell.autoawait`` configuration option and set it |
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49 | 54 | to :any:`False` to deactivate automatic wrapping of asynchronous code. You can also |
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50 | 55 | use the :magic:`%autoawait` magic to toggle the behavior at runtime:: |
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51 | 56 | |
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52 | 57 | In [1]: %autoawait False |
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53 | 58 | |
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54 | 59 | In [2]: %autoawait |
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55 | 60 | IPython autoawait is `Off`, and set to use `IPython.core.interactiveshell._asyncio_runner` |
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56 | 61 | |
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57 | 62 | |
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58 | 63 | |
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59 | 64 | By default IPython will assume integration with Python's provided |
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60 | 65 | :mod:`asyncio`, but integration with other libraries is provided. In particular |
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61 |
we provide experimental integration with the ``curio`` and ``trio`` library |
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66 | we provide experimental integration with the ``curio`` and ``trio`` library, the | |
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67 | later one being necessary if you require the ability to do nested call of | |
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68 | IPython's ``embed()`` functionality. | |
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62 | 69 | |
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63 | 70 | You can switch current integration by using the |
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64 | 71 | ``c.InteractiveShell.loop_runner`` option or the ``autoawait <name |
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65 | 72 | integration>`` magic. |
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66 | 73 | |
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67 | 74 | For example:: |
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68 | 75 | |
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69 | 76 | In [1]: %autoawait trio |
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70 | 77 | |
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71 | 78 | In [2]: import trio |
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72 | 79 | |
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73 | 80 | In [3]: async def child(i): |
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74 | 81 | ...: print(" child %s goes to sleep"%i) |
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75 | 82 | ...: await trio.sleep(2) |
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76 | 83 | ...: print(" child %s wakes up"%i) |
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77 | 84 | |
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78 | 85 | In [4]: print('parent start') |
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79 | 86 | ...: async with trio.open_nursery() as n: |
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80 | 87 | ...: for i in range(5): |
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81 | 88 | ...: n.spawn(child, i) |
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82 | 89 | ...: print('parent end') |
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83 | 90 | parent start |
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84 | 91 | child 2 goes to sleep |
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85 | 92 | child 0 goes to sleep |
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86 | 93 | child 3 goes to sleep |
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87 | 94 | child 1 goes to sleep |
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88 | 95 | child 4 goes to sleep |
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89 | 96 | <about 2 seconds pause> |
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90 | 97 | child 2 wakes up |
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91 | 98 | child 1 wakes up |
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92 | 99 | child 0 wakes up |
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93 | 100 | child 3 wakes up |
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94 | 101 | child 4 wakes up |
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95 | 102 | parent end |
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96 | 103 | |
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97 | 104 | |
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98 | 105 | In the above example, ``async with`` at top level scope is a syntax error in |
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99 | 106 | Python. |
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100 | 107 | |
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101 | 108 | Using this mode can have unexpected consequences if used in interaction with |
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102 | 109 | other features of IPython and various registered extensions. In particular if you |
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103 | 110 | are a direct or indirect user of the AST transformers, these may not apply to |
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104 | 111 | your code. |
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105 | 112 | |
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106 | The default loop, or runner does not run in the background, so top level | |
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107 | asynchronous code must finish for the REPL to allow you to enter more code. As | |
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108 | with usual Python semantic, the awaitables are started only when awaited for the | |
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109 | first time. That is to say, in first example, no network request is done between | |
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110 | ``In[1]`` and ``In[2]``. | |
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113 | When Using command line IPython, the default loop (or runner) does not process | |
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114 | in the background, so top level asynchronous code must finish for the REPL to | |
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115 | allow you to enter more code. As with usual Python semantic, the awaitables are | |
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116 | started only when awaited for the first time. That is to say, in first example, | |
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117 | no network request is done between ``In[1]`` and ``In[2]``. | |
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111 | 118 | |
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112 | 119 | |
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113 | 120 | Internals |
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114 | 121 | ========= |
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115 | 122 | |
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116 | As running asynchronous code is not supported in interactive REPL as of Python | |
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117 |
3. |
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118 |
It is interesting to understand how this works in order to |
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123 | As running asynchronous code is not supported in interactive REPL (as of Python | |
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124 | 3.7) we have to rely to a number of complex workaround to allow this to happen. | |
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125 | It is interesting to understand how this works in order to comprehend potential | |
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119 | 126 | bugs, or provide a custom runner. |
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120 | 127 | |
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121 | 128 | Among the many approaches that are at our disposition, we find only one that |
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122 |
suited out need. Under the hood we |
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123 |
and run it in global names |
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129 | suited out need. Under the hood we use the code object from a async-def function | |
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130 | and run it in global namespace after modifying it to not create a new | |
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131 | ``locals()`` scope:: | |
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124 | 132 | |
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125 | 133 | async def inner_async(): |
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126 | 134 | locals().update(**global_namespace) |
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127 | 135 | # |
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128 | 136 | # here is user code |
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129 | 137 | # |
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130 | 138 | return last_user_statement |
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131 | 139 | codeobj = modify(inner_async.__code__) |
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132 | 140 | coroutine = eval(codeobj, user_ns) |
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133 | 141 | display(loop_runner(coroutine)) |
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134 | 142 | |
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135 | 143 | |
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136 | 144 | |
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137 | 145 | The first thing you'll notice is that unlike classical ``exec``, there is only |
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138 | 146 |
one name |
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139 | 147 | scope. |
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140 | 148 | |
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141 | 149 | On top of the above there are significant modification to the AST of |
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142 | 150 | ``function``, and ``loop_runner`` can be arbitrary complex. So there is a |
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143 | 151 | significant overhead to this kind of code. |
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144 | 152 | |
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145 | 153 | By default the generated coroutine function will be consumed by Asyncio's |
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146 | 154 | ``loop_runner = asyncio.get_evenloop().run_until_complete()`` method. It is |
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147 | 155 | though possible to provide your own. |
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148 | 156 | |
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149 | 157 | A loop runner is a *synchronous* function responsible from running a coroutine |
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150 | 158 | object. |
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151 | 159 | |
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152 | 160 | The runner is responsible from ensuring that ``coroutine`` run to completion, |
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153 | 161 | and should return the result of executing the coroutine. Let's write a |
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154 | 162 | runner for ``trio`` that print a message when used as an exercise, ``trio`` is |
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155 | 163 | special as it usually prefer to run a function object and make a coroutine by |
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156 | 164 | itself, we can get around this limitation by wrapping it in an async-def without |
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157 | 165 | parameters and passing this value to ``trio``:: |
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158 | 166 | |
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159 | 167 | |
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160 | 168 | In [1]: import trio |
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161 | 169 | ...: from types import CoroutineType |
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162 | 170 | ...: |
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163 | 171 | ...: def trio_runner(coro:CoroutineType): |
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164 | 172 | ...: print('running asynchronous code') |
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165 | 173 | ...: async def corowrap(coro): |
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166 | 174 | ...: return await coro |
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167 | 175 | ...: return trio.run(corowrap, coro) |
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168 | 176 | |
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169 | 177 | We can set it up by passing it to ``%autoawait``:: |
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170 | 178 | |
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171 | 179 | In [2]: %autoawait trio_runner |
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172 | 180 | |
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173 | 181 | In [3]: async def async_hello(name): |
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174 | 182 | ...: await trio.sleep(1) |
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175 | 183 | ...: print(f'Hello {name} world !') |
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176 | 184 | ...: await trio.sleep(1) |
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177 | 185 | |
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178 | 186 | In [4]: await async_hello('async') |
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179 | 187 | running asynchronous code |
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180 | 188 | Hello async world ! |
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181 | 189 | |
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182 | 190 | |
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183 | 191 | Asynchronous programming in python (and in particular in the REPL) is still a |
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184 | relatively young subject. Feel free to contribute improvements to this codebase | |
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185 | and give us feedback. | |
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192 | relatively young subject. We expect some code to not behave as you expect, so | |
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193 | feel free to contribute improvements to this codebase and give us feedback. |
@@ -1,44 +1,72 b'' | |||
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1 | 1 | ===================== |
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2 | 2 | Development version |
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3 | 3 | ===================== |
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4 | 4 | |
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5 | 5 | This document describes in-flight development work. |
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6 | 6 | |
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7 | 7 | .. warning:: |
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8 | 8 | |
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9 | 9 | Please do not edit this file by hand (doing so will likely cause merge |
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10 | 10 | conflicts for other Pull Requests). Instead, create a new file in the |
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11 | 11 | `docs/source/whatsnew/pr` folder |
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12 | 12 | |
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13 | 13 | |
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14 | 14 | Released .... ...., 2017 |
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15 | 15 | |
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16 | 16 | |
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17 | 17 | Need to be updated: |
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18 | 18 | |
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19 | 19 | .. toctree:: |
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20 | 20 | :maxdepth: 2 |
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21 | 21 | :glob: |
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22 | 22 | |
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23 | 23 | pr/* |
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24 | 24 | |
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25 | 25 | IPython 6 feature a major improvement in the completion machinery which is now |
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26 | 26 | capable of completing non-executed code. It is also the first version of IPython |
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27 | 27 | to stop compatibility with Python 2, which is still supported on the bugfix only |
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28 | 28 | 5.x branch. Read below to have a non-exhaustive list of new features. |
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29 | 29 | |
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30 | 30 | Make sure you have pip > 9.0 before upgrading. |
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31 | 31 | You should be able to update by using: |
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32 | 32 | |
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33 | 33 | .. code:: |
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34 | 34 | |
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35 | 35 | pip install ipython --upgrade |
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36 | 36 | |
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37 | 37 | |
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38 | Autowait: Asynchronous REPL | |
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39 | =========================== | |
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40 | ||
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41 | Staring with IPython 7.0 and on Python 3.6+, IPython can automatically await | |
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42 | code at top level, you should not need to access an event loop or runner | |
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43 | yourself. To know more read the `autoawait`_ section of our docs, or try the | |
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44 | following code:: | |
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45 | ||
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46 | In [6]: from asyncio import sleep | |
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47 | ...: print('Going to sleep...') | |
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48 | ...: await sleep(3) | |
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49 | ...: print('Waking up') | |
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50 | Going to sleep... | |
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51 | Waking up | |
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52 | ||
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53 | Asynchronous code in a Notebook interface or any other frontend using the | |
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54 | Jupyter Protocol will need further updates of the IPykernel package. | |
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55 | ||
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56 | ||
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57 | Change to Nested Embed | |
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58 | ====================== | |
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59 | ||
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60 | The introduction of the ability to run async code had ripple effect on the | |
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61 | ability to use nested IPython. You may need to install the ``trio`` library | |
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62 | (version 05 at the time of this writing) to | |
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63 | have this feature working. | |
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64 | ||
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65 | ||
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38 | 66 | .. DO NOT EDIT THIS LINE BEFORE RELEASE. FEATURE INSERTION POINT. |
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39 | 67 | |
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40 | 68 | |
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41 | 69 | Backwards incompatible changes |
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42 | 70 | ------------------------------ |
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43 | 71 | |
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44 | 72 | .. DO NOT EDIT THIS LINE BEFORE RELEASE. INCOMPAT INSERTION POINT. |
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