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Small cleanups, no functional changes.
Small cleanups, no functional changes.

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displayhook.py
288 lines | 11.4 KiB | text/x-python | PythonLexer
# -*- coding: utf-8 -*-
"""Displayhook for IPython.
Authors:
* Fernando Perez
* Brian Granger
"""
#-----------------------------------------------------------------------------
# Copyright (C) 2008-2010 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 pprint import PrettyPrinter
pformat = PrettyPrinter().pformat
from IPython.config.configurable import Configurable
from IPython.core import prompts
import IPython.utils.generics
import IPython.utils.io
from IPython.utils.traitlets import Instance, Int
from IPython.utils.warn import warn
#-----------------------------------------------------------------------------
# Main displayhook class
#-----------------------------------------------------------------------------
# TODO: The DisplayHook class should be split into two classes, one that
# manages the prompts and their synchronization and another that just does the
# displayhook logic and calls into the prompt manager.
# TODO: Move the various attributes (cache_size, colors, input_sep,
# output_sep, output_sep2, ps1, ps2, ps_out, pad_left). 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.
Currently this class does more than just the displayhook logic and that
extra logic should eventually be moved out of here.
"""
shell = Instance('IPython.core.interactiveshell.InteractiveShellABC')
# Each call to the In[] prompt raises it by 1, even the first.
prompt_count = Int(0)
def __init__(self, shell=None, cache_size=1000,
colors='NoColor', input_sep='\n',
output_sep='\n', output_sep2='',
ps1 = None, ps2 = None, ps_out = None, pad_left=True,
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
self.input_sep = input_sep
# we need a reference to the user-level namespace
self.shell = shell
# Set input prompt strings and colors
if cache_size == 0:
if ps1.find('%n') > -1 or ps1.find(r'\#') > -1 \
or ps1.find(r'\N') > -1:
ps1 = '>>> '
if ps2.find('%n') > -1 or ps2.find(r'\#') > -1 \
or ps2.find(r'\N') > -1:
ps2 = '... '
self.ps1_str = self._set_prompt_str(ps1,'In [\\#]: ','>>> ')
self.ps2_str = self._set_prompt_str(ps2,' .\\D.: ','... ')
self.ps_out_str = self._set_prompt_str(ps_out,'Out[\\#]: ','')
self.color_table = prompts.PromptColors
self.prompt1 = prompts.Prompt1(self,sep=input_sep,prompt=self.ps1_str,
pad_left=pad_left)
self.prompt2 = prompts.Prompt2(self,prompt=self.ps2_str,pad_left=pad_left)
self.prompt_out = prompts.PromptOut(self,sep='',prompt=self.ps_out_str,
pad_left=pad_left)
self.set_colors(colors)
# Store the last prompt string each time, we need it for aligning
# continuation and auto-rewrite prompts
self.last_prompt = ''
self.output_sep = output_sep
self.output_sep2 = output_sep2
self._,self.__,self.___ = '','',''
self.pprint_types = map(type,[(),[],{}])
# these are deliberately global:
to_user_ns = {'_':self._,'__':self.__,'___':self.___}
self.shell.user_ns.update(to_user_ns)
def _set_prompt_str(self,p_str,cache_def,no_cache_def):
if p_str is None:
if self.do_full_cache:
return cache_def
else:
return no_cache_def
else:
return p_str
def set_colors(self, colors):
"""Set the active color scheme and configure colors for the three
prompt subsystems."""
# FIXME: This modifying of the global prompts.prompt_specials needs
# to be fixed. We need to refactor all of the prompts stuff to use
# proper configuration and traits notifications.
if colors.lower()=='nocolor':
prompts.prompt_specials = prompts.prompt_specials_nocolor
else:
prompts.prompt_specials = prompts.prompt_specials_color
self.color_table.set_active_scheme(colors)
self.prompt1.set_colors()
self.prompt2.set_colors()
self.prompt_out.set_colors()
#-------------------------------------------------------------------------
# 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:
if self.shell.input_hist[self.prompt_count].endswith(';\n'):
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."""
# Use write, not print which adds an extra space.
IPython.utils.io.Term.cout.write(self.output_sep)
outprompt = str(self.prompt_out)
if self.do_full_cache:
IPython.utils.io.Term.cout.write(outprompt)
# TODO: Make this method an extension point. The previous implementation
# has both a result_display hook as well as a result_display generic
# function to customize the repr on a per class basis. We need to rethink
# the hooks mechanism before doing this though.
def compute_result_repr(self, result):
"""Compute and return the repr of the object to be displayed.
This method only compute the string form of the repr and should NOT
actual print or write that to a stream. This method may also transform
the result itself, but the default implementation passes the original
through.
"""
try:
if self.shell.pprint:
result_repr = pformat(result)
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.
result_repr = '\n' + result_repr
else:
result_repr = repr(result)
except TypeError:
# This happens when result.__repr__ doesn't return a string,
# such as when it returns None.
result_repr = '\n'
return result, result_repr
def write_result_repr(self, result_repr):
# 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.
print >>IPython.utils.io.Term.cout, 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.user_ns.update({'_':self._,'__':self.__,'___':self.___})
# 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.user_ns.update(to_main)
self.shell.user_ns['_oh'][self.prompt_count] = result
def log_output(self, result):
"""Log the output."""
if self.shell.logger.log_output:
self.shell.logger.log_write(repr(result),'output')
def finish_displayhook(self):
"""Finish up all displayhook activities."""
IPython.utils.io.Term.cout.write(self.output_sep2)
IPython.utils.io.Term.cout.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()
result, result_repr = self.compute_result_repr(result)
self.write_result_repr(result_repr)
self.update_user_ns(result)
self.log_output(result)
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()
if '_' not in __builtin__.__dict__:
self.shell.user_ns.update({'_':None,'__':None, '___':None})
import gc
gc.collect() # xxx needed?