forked from ipython/ipython
/
displayhook.py
265 lines (217 loc) · 10.1 KB
/
displayhook.py
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
# -*- coding: utf-8 -*-
"""Displayhook for IPython.
This defines a callable class that IPython uses for `sys.displayhook`.
Authors:
* Fernando Perez
* Brian Granger
* Robert Kern
"""
#-----------------------------------------------------------------------------
# Copyright (C) 2008-2011 The IPython Development Team
# Copyright (C) 2001-2007 Fernando Perez <fperez@colorado.edu>
#
# Distributed under the terms of the BSD License. The full license is in
# the file COPYING, distributed as part of this software.
#-----------------------------------------------------------------------------
#-----------------------------------------------------------------------------
# Imports
#-----------------------------------------------------------------------------
import __builtin__
from IPython.config.configurable import Configurable
from IPython.utils import io
from IPython.utils.traitlets import Instance, List
from IPython.utils.warn import warn
#-----------------------------------------------------------------------------
# Main displayhook class
#-----------------------------------------------------------------------------
# TODO: Move the various attributes (cache_size, [others now moved]). Some
# of these are also attributes of InteractiveShell. They should be on ONE object
# only and the other objects should ask that one object for their values.
class DisplayHook(Configurable):
"""The custom IPython displayhook to replace sys.displayhook.
This class does many things, but the basic idea is that it is a callable
that gets called anytime user code returns a value.
"""
shell = Instance('IPython.core.interactiveshell.InteractiveShellABC')
def __init__(self, shell=None, cache_size=1000, config=None):
super(DisplayHook, self).__init__(shell=shell, config=config)
cache_size_min = 3
if cache_size <= 0:
self.do_full_cache = 0
cache_size = 0
elif cache_size < cache_size_min:
self.do_full_cache = 0
cache_size = 0
warn('caching was disabled (min value for cache size is %s).' %
cache_size_min,level=3)
else:
self.do_full_cache = 1
self.cache_size = cache_size
# we need a reference to the user-level namespace
self.shell = shell
self._,self.__,self.___ = '','',''
# these are deliberately global:
to_user_ns = {'_':self._,'__':self.__,'___':self.___}
self.shell.user_ns.update(to_user_ns)
@property
def prompt_count(self):
return self.shell.execution_count
#-------------------------------------------------------------------------
# Methods used in __call__. Override these methods to modify the behavior
# of the displayhook.
#-------------------------------------------------------------------------
def check_for_underscore(self):
"""Check if the user has set the '_' variable by hand."""
# If something injected a '_' variable in __builtin__, delete
# ipython's automatic one so we don't clobber that. gettext() in
# particular uses _, so we need to stay away from it.
if '_' in __builtin__.__dict__:
try:
del self.shell.user_ns['_']
except KeyError:
pass
def quiet(self):
"""Should we silence the display hook because of ';'?"""
# do not print output if input ends in ';'
try:
cell = self.shell.history_manager.input_hist_parsed[self.prompt_count]
if cell.rstrip().endswith(';'):
return True
except IndexError:
# some uses of ipshellembed may fail here
pass
return False
def start_displayhook(self):
"""Start the displayhook, initializing resources."""
pass
def write_output_prompt(self):
"""Write the output prompt.
The default implementation simply writes the prompt to
``io.stdout``.
"""
# Use write, not print which adds an extra space.
io.stdout.write(self.shell.separate_out)
outprompt = self.shell.prompt_manager.render('out')
if self.do_full_cache:
io.stdout.write(outprompt)
def compute_format_data(self, result):
"""Compute format data of the object to be displayed.
The format data is a generalization of the :func:`repr` of an object.
In the default implementation the format data is a :class:`dict` of
key value pair where the keys are valid MIME types and the values
are JSON'able data structure containing the raw data for that MIME
type. It is up to frontends to determine pick a MIME to to use and
display that data in an appropriate manner.
This method only computes the format data for the object and should
NOT actually print or write that to a stream.
Parameters
----------
result : object
The Python object passed to the display hook, whose format will be
computed.
Returns
-------
format_data : dict
A :class:`dict` whose keys are valid MIME types and values are
JSON'able raw data for that MIME type. It is recommended that
all return values of this should always include the "text/plain"
MIME type representation of the object.
"""
return self.shell.display_formatter.format(result)
def write_format_data(self, format_dict):
"""Write the format data dict to the frontend.
This default version of this method simply writes the plain text
representation of the object to ``io.stdout``. Subclasses should
override this method to send the entire `format_dict` to the
frontends.
Parameters
----------
format_dict : dict
The format dict for the object passed to `sys.displayhook`.
"""
# We want to print because we want to always make sure we have a
# newline, even if all the prompt separators are ''. This is the
# standard IPython behavior.
result_repr = format_dict['text/plain']
if '\n' in result_repr:
# So that multi-line strings line up with the left column of
# the screen, instead of having the output prompt mess up
# their first line.
# We use the prompt template instead of the expanded prompt
# because the expansion may add ANSI escapes that will interfere
# with our ability to determine whether or not we should add
# a newline.
prompt_template = self.shell.prompt_manager.out_template
if prompt_template and not prompt_template.endswith('\n'):
# But avoid extraneous empty lines.
result_repr = '\n' + result_repr
print >>io.stdout, result_repr
def update_user_ns(self, result):
"""Update user_ns with various things like _, __, _1, etc."""
# Avoid recursive reference when displaying _oh/Out
if result is not self.shell.user_ns['_oh']:
if len(self.shell.user_ns['_oh']) >= self.cache_size and self.do_full_cache:
warn('Output cache limit (currently '+
`self.cache_size`+' entries) hit.\n'
'Flushing cache and resetting history counter...\n'
'The only history variables available will be _,__,___ and _1\n'
'with the current result.')
self.flush()
# Don't overwrite '_' and friends if '_' is in __builtin__ (otherwise
# we cause buggy behavior for things like gettext).
if '_' not in __builtin__.__dict__:
self.___ = self.__
self.__ = self._
self._ = result
self.shell.push({'_':self._,
'__':self.__,
'___':self.___}, interactive=False)
# hackish access to top-level namespace to create _1,_2... dynamically
to_main = {}
if self.do_full_cache:
new_result = '_'+`self.prompt_count`
to_main[new_result] = result
self.shell.push(to_main, interactive=False)
self.shell.user_ns['_oh'][self.prompt_count] = result
def log_output(self, format_dict):
"""Log the output."""
if self.shell.logger.log_output:
self.shell.logger.log_write(format_dict['text/plain'], 'output')
self.shell.history_manager.output_hist_reprs[self.prompt_count] = \
format_dict['text/plain']
def finish_displayhook(self):
"""Finish up all displayhook activities."""
io.stdout.write(self.shell.separate_out2)
io.stdout.flush()
def __call__(self, result=None):
"""Printing with history cache management.
This is invoked everytime the interpreter needs to print, and is
activated by setting the variable sys.displayhook to it.
"""
self.check_for_underscore()
if result is not None and not self.quiet():
self.start_displayhook()
self.write_output_prompt()
format_dict = self.compute_format_data(result)
self.write_format_data(format_dict)
self.update_user_ns(result)
self.log_output(format_dict)
self.finish_displayhook()
def flush(self):
if not self.do_full_cache:
raise ValueError,"You shouldn't have reached the cache flush "\
"if full caching is not enabled!"
# delete auto-generated vars from global namespace
for n in range(1,self.prompt_count + 1):
key = '_'+`n`
try:
del self.shell.user_ns[key]
except: pass
self.shell.user_ns['_oh'].clear()
# Release our own references to objects:
self._, self.__, self.___ = '', '', ''
if '_' not in __builtin__.__dict__:
self.shell.user_ns.update({'_':None,'__':None, '___':None})
import gc
# TODO: Is this really needed?
gc.collect()