do not crash if prompt_count is 0 (detected with leo ipython plugin)

IPython/Prompts.py

@@ -1,621 +1,621 b''
 # -*- coding: utf-8 -*-
 """
 Classes for handling input/output prompts.
 
-$Id: Prompts.py 2928 2008-01-10 14:30:51Z vivainio $"""
+$Id: Prompts.py 3025 2008-02-07 15:45:43Z vivainio $"""
 
 #*****************************************************************************
 #       Copyright (C) 2001-2006 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.
 #*****************************************************************************
 
 from IPython import Release
 __author__  = '%s <%s>' % Release.authors['Fernando']
 __license__ = Release.license
 __version__ = Release.version
 
 #****************************************************************************
 # Required modules
 import __builtin__
 import os
 import socket
 import sys
 import time
 
 # IPython's own
 from IPython import ColorANSI
 from IPython.Itpl import ItplNS
 from IPython.ipstruct import Struct
 from IPython.macro import Macro
 from IPython.genutils import *
 from IPython.ipapi import TryNext
 
 #****************************************************************************
 #Color schemes for Prompts.
 
 PromptColors = ColorANSI.ColorSchemeTable()
 InputColors = ColorANSI.InputTermColors  # just a shorthand
 Colors = ColorANSI.TermColors  # just a shorthand
 
 PromptColors.add_scheme(ColorANSI.ColorScheme(
     'NoColor',
     in_prompt  = InputColors.NoColor,  # Input prompt
     in_number  = InputColors.NoColor,  # Input prompt number
     in_prompt2 = InputColors.NoColor, # Continuation prompt
     in_normal  = InputColors.NoColor,  # color off (usu. Colors.Normal)
     
     out_prompt = Colors.NoColor, # Output prompt
     out_number = Colors.NoColor, # Output prompt number
 
     normal = Colors.NoColor  # color off (usu. Colors.Normal)
     ))
 
 # make some schemes as instances so we can copy them for modification easily:
 __PColLinux =  ColorANSI.ColorScheme(
     'Linux',
     in_prompt  = InputColors.Green,
     in_number  = InputColors.LightGreen,
     in_prompt2 = InputColors.Green,
     in_normal  = InputColors.Normal,  # color off (usu. Colors.Normal)
 
     out_prompt = Colors.Red,
     out_number = Colors.LightRed,
 
     normal = Colors.Normal
     )
 # Don't forget to enter it into the table!
 PromptColors.add_scheme(__PColLinux)
 
 # Slightly modified Linux for light backgrounds
 __PColLightBG  = __PColLinux.copy('LightBG')
 
 __PColLightBG.colors.update(
     in_prompt  = InputColors.Blue,
     in_number  = InputColors.LightBlue,
     in_prompt2 = InputColors.Blue
 )
 PromptColors.add_scheme(__PColLightBG)
 
 del Colors,InputColors
 
 #-----------------------------------------------------------------------------
 def multiple_replace(dict, text):
     """ Replace in 'text' all occurences of any key in the given
     dictionary by its corresponding value.  Returns the new string."""
 
     # Function by Xavier Defrang, originally found at:
     # http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/81330
 
     # Create a regular expression  from the dictionary keys
     regex = re.compile("(%s)" % "|".join(map(re.escape, dict.keys())))
     # For each match, look-up corresponding value in dictionary
     return regex.sub(lambda mo: dict[mo.string[mo.start():mo.end()]], text)
 
 #-----------------------------------------------------------------------------
 # Special characters that can be used in prompt templates, mainly bash-like
 
 # If $HOME isn't defined (Windows), make it an absurd string so that it can
 # never be expanded out into '~'.  Basically anything which can never be a
 # reasonable directory name will do, we just want the $HOME -> '~' operation
 # to become a no-op.  We pre-compute $HOME here so it's not done on every
 # prompt call.
 
 # FIXME:
 
 # - This should be turned into a class which does proper namespace management,
 # since the prompt specials need to be evaluated in a certain namespace.
 # Currently it's just globals, which need to be managed manually by code
 # below.
 
 # - I also need to split up the color schemes from the prompt specials
 # somehow.  I don't have a clean design for that quite yet.
 
 HOME = os.environ.get("HOME","//////:::::ZZZZZ,,,~~~")
 
 # We precompute a few more strings here for the prompt_specials, which are
 # fixed once ipython starts.  This reduces the runtime overhead of computing
 # prompt strings.
 USER           = os.environ.get("USER")
 HOSTNAME       = socket.gethostname()
 HOSTNAME_SHORT = HOSTNAME.split(".")[0]
 ROOT_SYMBOL    = "$#"[os.name=='nt' or os.getuid()==0]
 
 prompt_specials_color = {
     # Prompt/history count
     '%n' : '${self.col_num}' '${self.cache.prompt_count}' '${self.col_p}',
     r'\#': '${self.col_num}' '${self.cache.prompt_count}' '${self.col_p}',
     # Just the prompt counter number, WITHOUT any coloring wrappers, so users
     # can get numbers displayed in whatever color they want.
     r'\N': '${self.cache.prompt_count}',
     # Prompt/history count, with the actual digits replaced by dots.  Used
     # mainly in continuation prompts (prompt_in2)
     r'\D': '${"."*len(str(self.cache.prompt_count))}',
     # Current working directory
     r'\w': '${os.getcwd()}',
     # Current time
     r'\t' : '${time.strftime("%H:%M:%S")}',
     # Basename of current working directory.
     # (use os.sep to make this portable across OSes)
     r'\W' : '${os.getcwd().split("%s")[-1]}' % os.sep,
     # These X<N> are an extension to the normal bash prompts.  They return
     # N terms of the path, after replacing $HOME with '~'
     r'\X0': '${os.getcwd().replace("%s","~")}' % HOME,
     r'\X1': '${self.cwd_filt(1)}',
     r'\X2': '${self.cwd_filt(2)}',
     r'\X3': '${self.cwd_filt(3)}',
     r'\X4': '${self.cwd_filt(4)}',
     r'\X5': '${self.cwd_filt(5)}',
     # Y<N> are similar to X<N>, but they show '~' if it's the directory
     # N+1 in the list.  Somewhat like %cN in tcsh.
     r'\Y0': '${self.cwd_filt2(0)}',
     r'\Y1': '${self.cwd_filt2(1)}',
     r'\Y2': '${self.cwd_filt2(2)}',
     r'\Y3': '${self.cwd_filt2(3)}',
     r'\Y4': '${self.cwd_filt2(4)}',
     r'\Y5': '${self.cwd_filt2(5)}',
     # Hostname up to first .
     r'\h': HOSTNAME_SHORT,
     # Full hostname
     r'\H': HOSTNAME,
     # Username of current user
     r'\u': USER,
     # Escaped '\'
     '\\\\': '\\',
     # Newline
     r'\n': '\n',
     # Carriage return
     r'\r': '\r',
     # Release version
     r'\v': __version__,
     # Root symbol ($ or #)
     r'\$': ROOT_SYMBOL,
     }
 
 # A copy of the prompt_specials dictionary but with all color escapes removed,
 # so we can correctly compute the prompt length for the auto_rewrite method.
 prompt_specials_nocolor = prompt_specials_color.copy()
 prompt_specials_nocolor['%n'] = '${self.cache.prompt_count}'
 prompt_specials_nocolor[r'\#'] = '${self.cache.prompt_count}'
 
 # Add in all the InputTermColors color escapes as valid prompt characters.
 # They all get added as \\C_COLORNAME, so that we don't have any conflicts
 # with a color name which may begin with a letter used by any other of the
 # allowed specials.  This of course means that \\C will never be allowed for
 # anything else.
 input_colors = ColorANSI.InputTermColors
 for _color in dir(input_colors):
     if _color[0] != '_':
         c_name = r'\C_'+_color
         prompt_specials_color[c_name] = getattr(input_colors,_color)
         prompt_specials_nocolor[c_name] = ''
 
 # we default to no color for safety.  Note that prompt_specials is a global
 # variable used by all prompt objects.
 prompt_specials = prompt_specials_nocolor
 
 #-----------------------------------------------------------------------------
 def str_safe(arg):
     """Convert to a string, without ever raising an exception.
 
     If str(arg) fails, <ERROR: ... > is returned, where ... is the exception
     error message."""
 
     try:
         out = str(arg)
     except UnicodeError:
         try:
             out = arg.encode('utf_8','replace')
         except Exception,msg:
             # let's keep this little duplication here, so that the most common
             # case doesn't suffer from a double try wrapping.
             out = '<ERROR: %s>' % msg
     except Exception,msg:
         out = '<ERROR: %s>' % msg
     return out
 
 class BasePrompt(object):
     """Interactive prompt similar to Mathematica's."""
 
     def _get_p_template(self):
         return self._p_template
 
     def _set_p_template(self,val):
         self._p_template = val
         self.set_p_str()
 
     p_template = property(_get_p_template,_set_p_template,
                           doc='Template for prompt string creation')
 
     def __init__(self,cache,sep,prompt,pad_left=False):
 
         # Hack: we access information about the primary prompt through the
         # cache argument.  We need this, because we want the secondary prompt
         # to be aligned with the primary one.  Color table info is also shared
         # by all prompt classes through the cache.  Nice OO spaghetti code!
         self.cache = cache
         self.sep = sep
         
         # regexp to count the number of spaces at the end of a prompt
         # expression, useful for prompt auto-rewriting
         self.rspace = re.compile(r'(\s*)$')
         # Flag to left-pad prompt strings to match the length of the primary
         # prompt
         self.pad_left = pad_left
 
         # Set template to create each actual prompt (where numbers change).
         # Use a property
         self.p_template = prompt
         self.set_p_str()
 
     def set_p_str(self):
         """ Set the interpolating prompt strings.
 
         This must be called every time the color settings change, because the
         prompt_specials global may have changed."""
 
         import os,time  # needed in locals for prompt string handling
         loc = locals()
         try:
             self.p_str = ItplNS('%s%s%s' %
                                 ('${self.sep}${self.col_p}',
                                  multiple_replace(prompt_specials, self.p_template),
                                  '${self.col_norm}'),self.cache.user_ns,loc)
     
             self.p_str_nocolor = ItplNS(multiple_replace(prompt_specials_nocolor,
                                                          self.p_template),
                                         self.cache.user_ns,loc)
         except:
             print "Illegal prompt template (check $ usage!):",self.p_template
             self.p_str = self.p_template
             self.p_str_nocolor = self.p_template
 
     def write(self,msg):  # dbg
         sys.stdout.write(msg)
         return ''
 
     def __str__(self):
         """Return a string form of the prompt.
 
         This for is useful for continuation and output prompts, since it is
         left-padded to match lengths with the primary one (if the
         self.pad_left attribute is set)."""
 
         out_str = str_safe(self.p_str)
         if self.pad_left:
             # We must find the amount of padding required to match lengths,
             # taking the color escapes (which are invisible on-screen) into
             # account.
             esc_pad = len(out_str) - len(str_safe(self.p_str_nocolor))
             format = '%%%ss' % (len(str(self.cache.last_prompt))+esc_pad)
             return format % out_str
         else:
             return out_str
 
     # these path filters are put in as methods so that we can control the
     # namespace where the prompt strings get evaluated
     def cwd_filt(self,depth):
         """Return the last depth elements of the current working directory.
 
         $HOME is always replaced with '~'.
         If depth==0, the full path is returned."""
 
         cwd = os.getcwd().replace(HOME,"~")
         out = os.sep.join(cwd.split(os.sep)[-depth:])
         if out:
             return out
         else:
             return os.sep
 
     def cwd_filt2(self,depth):
         """Return the last depth elements of the current working directory.
 
         $HOME is always replaced with '~'.
         If depth==0, the full path is returned."""
 
         full_cwd = os.getcwd()
         cwd = full_cwd.replace(HOME,"~").split(os.sep)
         if '~' in cwd and len(cwd) == depth+1:
             depth += 1
         drivepart = ''
         if sys.platform == 'win32' and len(cwd) > depth:
             drivepart = os.path.splitdrive(full_cwd)[0]
         out = drivepart + '/'.join(cwd[-depth:])
 
         if out:
             return out
         else:
             return os.sep
 
     def __nonzero__(self):
         """Implement boolean behavior.
 
         Checks whether the p_str attribute is non-empty"""
 
         return bool(self.p_template)
 
 class Prompt1(BasePrompt):
     """Input interactive prompt similar to Mathematica's."""
 
     def __init__(self,cache,sep='\n',prompt='In [\\#]: ',pad_left=True):
         BasePrompt.__init__(self,cache,sep,prompt,pad_left)
 
     def set_colors(self):
         self.set_p_str()
         Colors = self.cache.color_table.active_colors # shorthand
         self.col_p = Colors.in_prompt
         self.col_num = Colors.in_number
         self.col_norm = Colors.in_normal
         # We need a non-input version of these escapes for the '--->'
         # auto-call prompts used in the auto_rewrite() method.
         self.col_p_ni = self.col_p.replace('\001','').replace('\002','') 
         self.col_norm_ni = Colors.normal        
         
     def __str__(self):
         self.cache.prompt_count += 1
         self.cache.last_prompt = str_safe(self.p_str_nocolor).split('\n')[-1]
         return str_safe(self.p_str)
 
     def auto_rewrite(self):
         """Print a string of the form '--->' which lines up with the previous
         input string. Useful for systems which re-write the user input when
         handling automatically special syntaxes."""
 
         curr = str(self.cache.last_prompt)
         nrspaces = len(self.rspace.search(curr).group())
         return '%s%s>%s%s' % (self.col_p_ni,'-'*(len(curr)-nrspaces-1),
                               ' '*nrspaces,self.col_norm_ni)
 
 class PromptOut(BasePrompt):
     """Output interactive prompt similar to Mathematica's."""
 
     def __init__(self,cache,sep='',prompt='Out[\\#]: ',pad_left=True):
         BasePrompt.__init__(self,cache,sep,prompt,pad_left)
         if not self.p_template:
             self.__str__ = lambda: ''
 
     def set_colors(self):
         self.set_p_str()
         Colors = self.cache.color_table.active_colors # shorthand
         self.col_p = Colors.out_prompt
         self.col_num = Colors.out_number
         self.col_norm = Colors.normal
 
 class Prompt2(BasePrompt):
     """Interactive continuation prompt."""
     
     def __init__(self,cache,prompt='   .\\D.: ',pad_left=True):
         self.cache = cache
         self.p_template = prompt
         self.pad_left = pad_left
         self.set_p_str()
 
     def set_p_str(self):
         import os,time  # needed in locals for prompt string handling
         loc = locals()
         self.p_str = ItplNS('%s%s%s' %
                             ('${self.col_p2}',
                              multiple_replace(prompt_specials, self.p_template),
                              '$self.col_norm'),
                             self.cache.user_ns,loc)
         self.p_str_nocolor = ItplNS(multiple_replace(prompt_specials_nocolor,
                                                      self.p_template),
                                     self.cache.user_ns,loc)
 
     def set_colors(self):
         self.set_p_str()
         Colors = self.cache.color_table.active_colors
         self.col_p2 = Colors.in_prompt2
         self.col_norm = Colors.in_normal
         # FIXME (2004-06-16) HACK: prevent crashes for users who haven't
         # updated their prompt_in2 definitions.  Remove eventually.
         self.col_p = Colors.out_prompt
         self.col_num = Colors.out_number
 
 
 #-----------------------------------------------------------------------------
 class CachedOutput:
     """Class for printing output from calculations while keeping a cache of
     reults. It dynamically creates global variables prefixed with _ which
     contain these results.
 
     Meant to be used as a sys.displayhook replacement, providing numbered
     prompts and cache services.
 
     Initialize with initial and final values for cache counter (this defines
     the maximum size of the cache."""
 
     def __init__(self,shell,cache_size,Pprint,
                  colors='NoColor',input_sep='\n',
                  output_sep='\n',output_sep2='',
                  ps1 = None, ps2 = None,ps_out = None,pad_left=True):
 
         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
         self.user_ns = shell.user_ns
         # and to the user's input
         self.input_hist = shell.input_hist
         # and to the user's logger, for logging output
         self.logger = shell.logger
 
         # 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 = PromptColors
         self.prompt1 = Prompt1(self,sep=input_sep,prompt=self.ps1_str,
                                pad_left=pad_left)
         self.prompt2 = Prompt2(self,prompt=self.ps2_str,pad_left=pad_left)
         self.prompt_out = PromptOut(self,sep='',prompt=self.ps_out_str,
                                     pad_left=pad_left)
         self.set_colors(colors)
 
         # other more normal stuff
         # b/c each call to the In[] prompt raises it by 1, even the first.
         self.prompt_count = 0
         # Store the last prompt string each time, we need it for aligning
         # continuation and auto-rewrite prompts
         self.last_prompt = ''
         self.Pprint = Pprint
         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.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: the prompt_specials global should be gobbled inside this
         # class instead.  Do it when cleaning up the whole 3-prompt system.
         global prompt_specials
         if colors.lower()=='nocolor':
             prompt_specials = prompt_specials_nocolor
         else:
             prompt_specials = prompt_specials_color
         
         self.color_table.set_active_scheme(colors)
         self.prompt1.set_colors()
         self.prompt2.set_colors()
         self.prompt_out.set_colors()
 
     def __call__(self,arg=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."""
 
         # 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.user_ns['_']
             except KeyError:
                 pass
         if arg is not None:
             cout_write = Term.cout.write # fast lookup
             # first handle the cache and counters
 
             # do not print output if input ends in ';'
-            if self.input_hist[self.prompt_count].endswith(';\n'):
+            if self.prompt_count and self.input_hist[self.prompt_count].endswith(';\n'):
                 return
             # don't use print, puts an extra space
             cout_write(self.output_sep)
             outprompt = self.shell.hooks.generate_output_prompt()
             if self.do_full_cache:
                 cout_write(outprompt)
 
             # and now call a possibly user-defined print mechanism
             manipulated_val = self.display(arg)
             
             # user display hooks can change the variable to be stored in
             # output history
             
             if manipulated_val is not None:
                 arg = manipulated_val
                 
             # avoid recursive reference when displaying _oh/Out
             if arg is not self.user_ns['_oh']:
                 self.update(arg)
 
             if self.logger.log_output:
                 self.logger.log_write(repr(arg),'output')
             cout_write(self.output_sep2)
             Term.cout.flush()
 
     def _display(self,arg):
         """Default printer method, uses pprint.
 
         Do ip.set_hook("result_display", my_displayhook) for custom result
         display, e.g. when your own objects need special formatting.
         """
         try:
             return IPython.generics.result_display(arg)
         except TryNext:            
             return self.shell.hooks.result_display(arg)
 
     # Assign the default display method:
     display = _display
 
     def update(self,arg):
         #print '***cache_count', self.cache_count # dbg
         if len(self.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._ = arg
             self.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] = arg
             self.user_ns.update(to_main)
             self.user_ns['_oh'][self.prompt_count] = arg
 
     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.user_ns[key]
             except: pass
         self.user_ns['_oh'].clear()
         
         if '_' not in __builtin__.__dict__:
             self.user_ns.update({'_':None,'__':None, '___':None})
         import gc
         gc.collect() # xxx needed?