BUG: For multiline outputs, conditionally prepend a newline if necessary. Move this code to where we actually write the output. Frontends should be able to decide whether to use this or not.

IPython/core/displayhook.py

@@ -1,301 +1,304 b''
 # -*- 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 <[e-mail]>
 #
 #  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.core import prompts
 import IPython.utils.generics
 import IPython.utils.io
 from IPython.utils.traitlets import Instance, List
 from IPython.utils.warn import warn
 from IPython.core.formatters import DefaultFormatter
 
 #-----------------------------------------------------------------------------
 # 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')
 
     # The default formatter.
     default_formatter = Instance('IPython.core.formatters.FormatterABC')
     def _default_formatter_default(self):
         # FIXME: backwards compatibility for the InteractiveShell.pprint option?
         return DefaultFormatter(config=self.config)
 
     # Any additional FormatterABC instances we use.
     # FIXME: currently unused.
     extra_formatters = List(config=True)
 
     # 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.___ = '','',''
 
         # 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
 
     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)
 
     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
         actually print or write that to a stream.
         """
         result_repr = self.default_formatter(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.
-            outprompt = str(self.prompt_out)
-            if outprompt and not outprompt.endswith('\n'):
-                # But avoid extraneous empty lines.
-                result_repr = '\n' + result_repr
-
         extra_formats = []
         for f in self.extra_formatters:
             try:
                 data = f(result)
             except Exception:
                 # FIXME: log the exception.
                 continue
             if data is not None:
                 extra_formats.append((f.id, f.format, data))
 
         return result_repr, extra_formats
 
     def write_result_repr(self, result_repr, extra_formats):
         # 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.
+        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 ps_out_str 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.
+            if self.ps_out_str and not self.ps_out_str.endswith('\n'):
+                # But avoid extraneous empty lines.
+                result_repr = '\n' + result_repr
+
         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_repr, extra_formats = self.compute_result_repr(result)
             self.write_result_repr(result_repr, extra_formats)
             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?