##// END OF EJS Templates
no f-strings
Matthias Bussonnier -
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@@ -1,107 +1,107 b''
1 """
1 """
2 Async helper function that are invalid syntax on Python 3.5 and below.
2 Async helper function that are invalid syntax on Python 3.5 and below.
3
3
4 Known limitation and possible improvement.
4 Known limitation and possible improvement.
5
5
6 Top level code that contain a return statement (instead of, or in addition to
6 Top level code that contain a return statement (instead of, or in addition to
7 await) will be detected as requiring being wrapped in async calls. This should
7 await) will be detected as requiring being wrapped in async calls. This should
8 be prevented as early return will not work.
8 be prevented as early return will not work.
9 """
9 """
10
10
11
11
12 import ast
12 import ast
13 import sys
13 import sys
14 import inspect
14 import inspect
15 from textwrap import dedent, indent
15 from textwrap import dedent, indent
16 from types import CodeType
16 from types import CodeType
17
17
18
18
19 def _asyncio_runner(coro):
19 def _asyncio_runner(coro):
20 """
20 """
21 Handler for asyncio autoawait
21 Handler for asyncio autoawait
22 """
22 """
23 import asyncio
23 import asyncio
24
24
25 return asyncio.get_event_loop().run_until_complete(coro)
25 return asyncio.get_event_loop().run_until_complete(coro)
26
26
27
27
28 def _curio_runner(coroutine):
28 def _curio_runner(coroutine):
29 """
29 """
30 handler for curio autoawait
30 handler for curio autoawait
31 """
31 """
32 import curio
32 import curio
33
33
34 return curio.run(coroutine)
34 return curio.run(coroutine)
35
35
36
36
37 def _trio_runner(async_fn):
37 def _trio_runner(async_fn):
38 import trio
38 import trio
39 async def loc(coro):
39 async def loc(coro):
40 """
40 """
41 We need the dummy no-op async def to protect from
41 We need the dummy no-op async def to protect from
42 trio's internal. See https://github.com/python-trio/trio/issues/89
42 trio's internal. See https://github.com/python-trio/trio/issues/89
43 """
43 """
44 return await coro
44 return await coro
45 return trio.run(loc, async_fn)
45 return trio.run(loc, async_fn)
46
46
47
47
48 def _pseudo_sync_runner(coro):
48 def _pseudo_sync_runner(coro):
49 """
49 """
50 A runner that does not really allow async execution, and just advance the coroutine.
50 A runner that does not really allow async execution, and just advance the coroutine.
51
51
52 See discussion in https://github.com/python-trio/trio/issues/608,
52 See discussion in https://github.com/python-trio/trio/issues/608,
53
53
54 Credit to Nathaniel Smith
54 Credit to Nathaniel Smith
55
55
56 """
56 """
57 try:
57 try:
58 coro.send(None)
58 coro.send(None)
59 except StopIteration as exc:
59 except StopIteration as exc:
60 return exc.value
60 return exc.value
61 else:
61 else:
62 # TODO: do not raise but return an execution result with the right info.
62 # TODO: do not raise but return an execution result with the right info.
63 raise RuntimeError(f"{coro.__name__!r} needs a real async loop")
63 raise RuntimeError("{coro_name!r} needs a real async loop".format(coro_name=coro.__name__))
64
64
65
65
66 def _asyncify(code: str) -> str:
66 def _asyncify(code: str) -> str:
67 """wrap code in async def definition.
67 """wrap code in async def definition.
68
68
69 And setup a bit of context to run it later.
69 And setup a bit of context to run it later.
70 """
70 """
71 res = dedent(
71 res = dedent(
72 """
72 """
73 async def __wrapper__():
73 async def __wrapper__():
74 try:
74 try:
75 {usercode}
75 {usercode}
76 finally:
76 finally:
77 locals()
77 locals()
78 """
78 """
79 ).format(usercode=indent(code, " " * 8)[8:])
79 ).format(usercode=indent(code, " " * 8)[8:])
80 return res
80 return res
81
81
82
82
83 def _should_be_async(cell: str) -> bool:
83 def _should_be_async(cell: str) -> bool:
84 """Detect if a block of code need to be wrapped in an `async def`
84 """Detect if a block of code need to be wrapped in an `async def`
85
85
86 Attempt to parse the block of code, it it compile we're fine.
86 Attempt to parse the block of code, it it compile we're fine.
87 Otherwise we wrap if and try to compile.
87 Otherwise we wrap if and try to compile.
88
88
89 If it works, assume it should be async. Otherwise Return False.
89 If it works, assume it should be async. Otherwise Return False.
90
90
91 Not handled yet: If the block of code has a return statement as the top
91 Not handled yet: If the block of code has a return statement as the top
92 level, it will be seen as async. This is a know limitation.
92 level, it will be seen as async. This is a know limitation.
93 """
93 """
94
94
95 try:
95 try:
96 # we can't limit ourself to ast.parse, as it __accepts__ to parse on
96 # we can't limit ourself to ast.parse, as it __accepts__ to parse on
97 # 3.7+, but just does not _compile_
97 # 3.7+, but just does not _compile_
98 compile(cell, "<>", "exec")
98 compile(cell, "<>", "exec")
99 return False
99 return False
100 except SyntaxError:
100 except SyntaxError:
101 try:
101 try:
102 ast.parse(_asyncify(cell))
102 ast.parse(_asyncify(cell))
103 # TODO verify ast has not "top level" return or yield.
103 # TODO verify ast has not "top level" return or yield.
104 except SyntaxError:
104 except SyntaxError:
105 return False
105 return False
106 return True
106 return True
107 return False
107 return False
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