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Backport PR #9976: Let IPython.lib.guisupport detect terminal-integrated event loops...
Backport PR #9976: Let IPython.lib.guisupport detect terminal-integrated event loops Closes gh-9974 This is a bit more invasive than most backported changes, but it fixes a regression in IPython 5. My thinking: - The `guisupport` APIs that worked before should continue working until/unless we deprecate them. - There should be a common way to check if an event loop is already running in both the terminal and an IPython kernel. - It should be possible to check for any event loop, not just Qt and Wx (which `guisupport` has checks for). My plan is to make a public attribute `shell.active_eventloop`, which is either None or a string naming the event loop which IPython will run when waiting for input. E.g. `qt` or `gtk3`. (Todo: should we also expose the event loop object in cases where there is one? Not sure if anything useful can be done with it). This PR adds that attribute for terminal IPython; if we agree on it I'll make a separate PR for ipykernel. The functions in guisupport then become a convenient shortcut for checking this, and we can decide whether to deprecate them in favour or something more uniform, or add similar convenience functions for other common event loops. Signed-off-by: Thomas Kluyver <thomas@kluyver.me.uk>

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magics.py
207 lines | 7.2 KiB | text/x-python | PythonLexer
"""Extra magics for terminal use."""
# Copyright (c) IPython Development Team.
# Distributed under the terms of the Modified BSD License.
from __future__ import print_function
from logging import error
import os
import sys
from IPython.core.error import TryNext, UsageError
from IPython.core.inputsplitter import IPythonInputSplitter
from IPython.core.magic import Magics, magics_class, line_magic
from IPython.lib.clipboard import ClipboardEmpty
from IPython.utils.text import SList, strip_email_quotes
from IPython.utils import py3compat
def get_pasted_lines(sentinel, l_input=py3compat.input, quiet=False):
""" Yield pasted lines until the user enters the given sentinel value.
"""
if not quiet:
print("Pasting code; enter '%s' alone on the line to stop or use Ctrl-D." \
% sentinel)
prompt = ":"
else:
prompt = ""
while True:
try:
l = py3compat.str_to_unicode(l_input(prompt))
if l == sentinel:
return
else:
yield l
except EOFError:
print('<EOF>')
return
@magics_class
class TerminalMagics(Magics):
def __init__(self, shell):
super(TerminalMagics, self).__init__(shell)
self.input_splitter = IPythonInputSplitter()
def store_or_execute(self, block, name):
""" Execute a block, or store it in a variable, per the user's request.
"""
if name:
# If storing it for further editing
self.shell.user_ns[name] = SList(block.splitlines())
print("Block assigned to '%s'" % name)
else:
b = self.preclean_input(block)
self.shell.user_ns['pasted_block'] = b
self.shell.using_paste_magics = True
try:
self.shell.run_cell(b)
finally:
self.shell.using_paste_magics = False
def preclean_input(self, block):
lines = block.splitlines()
while lines and not lines[0].strip():
lines = lines[1:]
return strip_email_quotes('\n'.join(lines))
def rerun_pasted(self, name='pasted_block'):
""" Rerun a previously pasted command.
"""
b = self.shell.user_ns.get(name)
# Sanity checks
if b is None:
raise UsageError('No previous pasted block available')
if not isinstance(b, py3compat.string_types):
raise UsageError(
"Variable 'pasted_block' is not a string, can't execute")
print("Re-executing '%s...' (%d chars)"% (b.split('\n',1)[0], len(b)))
self.shell.run_cell(b)
@line_magic
def autoindent(self, parameter_s = ''):
"""Toggle autoindent on/off (if available)."""
self.shell.set_autoindent()
print("Automatic indentation is:",['OFF','ON'][self.shell.autoindent])
@line_magic
def cpaste(self, parameter_s=''):
"""Paste & execute a pre-formatted code block from clipboard.
You must terminate the block with '--' (two minus-signs) or Ctrl-D
alone on the line. You can also provide your own sentinel with '%paste
-s %%' ('%%' is the new sentinel for this operation).
The block is dedented prior to execution to enable execution of method
definitions. '>' and '+' characters at the beginning of a line are
ignored, to allow pasting directly from e-mails, diff files and
doctests (the '...' continuation prompt is also stripped). The
executed block is also assigned to variable named 'pasted_block' for
later editing with '%edit pasted_block'.
You can also pass a variable name as an argument, e.g. '%cpaste foo'.
This assigns the pasted block to variable 'foo' as string, without
dedenting or executing it (preceding >>> and + is still stripped)
'%cpaste -r' re-executes the block previously entered by cpaste.
'%cpaste -q' suppresses any additional output messages.
Do not be alarmed by garbled output on Windows (it's a readline bug).
Just press enter and type -- (and press enter again) and the block
will be what was just pasted.
IPython statements (magics, shell escapes) are not supported (yet).
See also
--------
paste: automatically pull code from clipboard.
Examples
--------
::
In [8]: %cpaste
Pasting code; enter '--' alone on the line to stop.
:>>> a = ["world!", "Hello"]
:>>> print " ".join(sorted(a))
:--
Hello world!
"""
opts, name = self.parse_options(parameter_s, 'rqs:', mode='string')
if 'r' in opts:
self.rerun_pasted()
return
quiet = ('q' in opts)
sentinel = opts.get('s', u'--')
block = '\n'.join(get_pasted_lines(sentinel, quiet=quiet))
self.store_or_execute(block, name)
@line_magic
def paste(self, parameter_s=''):
"""Paste & execute a pre-formatted code block from clipboard.
The text is pulled directly from the clipboard without user
intervention and printed back on the screen before execution (unless
the -q flag is given to force quiet mode).
The block is dedented prior to execution to enable execution of method
definitions. '>' and '+' characters at the beginning of a line are
ignored, to allow pasting directly from e-mails, diff files and
doctests (the '...' continuation prompt is also stripped). The
executed block is also assigned to variable named 'pasted_block' for
later editing with '%edit pasted_block'.
You can also pass a variable name as an argument, e.g. '%paste foo'.
This assigns the pasted block to variable 'foo' as string, without
executing it (preceding >>> and + is still stripped).
Options:
-r: re-executes the block previously entered by cpaste.
-q: quiet mode: do not echo the pasted text back to the terminal.
IPython statements (magics, shell escapes) are not supported (yet).
See also
--------
cpaste: manually paste code into terminal until you mark its end.
"""
opts, name = self.parse_options(parameter_s, 'rq', mode='string')
if 'r' in opts:
self.rerun_pasted()
return
try:
block = self.shell.hooks.clipboard_get()
except TryNext as clipboard_exc:
message = getattr(clipboard_exc, 'args')
if message:
error(message[0])
else:
error('Could not get text from the clipboard.')
return
except ClipboardEmpty:
raise UsageError("The clipboard appears to be empty")
# By default, echo back to terminal unless quiet mode is requested
if 'q' not in opts:
write = self.shell.write
write(self.shell.pycolorize(block))
if not block.endswith('\n'):
write('\n')
write("## -- End pasted text --\n")
self.store_or_execute(block, name)
# Class-level: add a '%cls' magic only on Windows
if sys.platform == 'win32':
@line_magic
def cls(self, s):
"""Clear screen.
"""
os.system("cls")