IPython/gui/wx/ipython_view.py

#!/usr/bin/python
# -*- coding: iso-8859-15 -*-
'''
Provides IPython WX console widget.

@author: Laurent Dufrechou
laurent.dufrechou _at_ gmail.com
This WX widget is based on the original work of Eitan Isaacson
that provided the console for the GTK toolkit.

Original work from:
@author: Eitan Isaacson
@organization: IBM Corporation
@copyright: Copyright (c) 2007 IBM Corporation
@license: BSD

All rights reserved. This program and the accompanying materials are made
available under the terms of the BSD which accompanies this distribution, and
is available at U{http://www.opensource.org/licenses/bsd-license.php}
'''

__version__ = 0.8
__author__  = "Laurent Dufrechou"
__email__   = "laurent.dufrechou _at_ gmail.com"
__license__ = "BSD"

import wx
import wx.stc  as  stc
import wx.lib.newevent

import re
import sys
import os
import locale
import time
from ThreadEx import Thread
from StringIO import StringIO

try:
        import IPython
except Exception,e:
        raise "Error importing IPython (%s)" % str(e)

class IterableIPShell(Thread):
    '''
    Create an IPython instance inside a dedicated thread.
    Does not start a blocking event loop, instead allow single iterations.
    This allows embedding in any GUI without blockage.
    The thread is a slave one, in that it doesn't interact directly with the GUI.
    Note Thread class comes from ThreadEx that supports asynchroneous function call
    via raise_exc()
    '''

    def __init__(self,argv=[],user_ns=None,user_global_ns=None,
                 cin=None, cout=None, cerr=None,
                 exit_handler=None,time_loop = 0.1):
        '''
        @param argv: Command line options for IPython
        @type argv: list
        @param user_ns: User namespace.
        @type user_ns: dictionary
        @param user_global_ns: User global namespace.
        @type user_global_ns: dictionary.
        @param cin: Console standard input.
        @type cin: IO stream
        @param cout: Console standard output.
        @type cout: IO stream
        @param cerr: Console standard error.
        @type cerr: IO stream
        @param exit_handler: Replacement for builtin exit() function
        @type exit_handler: function
        @param time_loop: Define the sleep time between two thread's loop
        @type int
        '''
        Thread.__init__(self)

        #first we redefine in/out/error functions of IPython 
        if cin:
            IPython.Shell.Term.cin = cin
        if cout:
            IPython.Shell.Term.cout = cout
        if cerr:
            IPython.Shell.Term.cerr = cerr
        
        # This is to get rid of the blockage that accurs during
        # IPython.Shell.InteractiveShell.user_setup()
        IPython.iplib.raw_input = lambda x: None

        self._term = IPython.genutils.IOTerm(cin=cin, cout=cout, cerr=cerr)

        excepthook = sys.excepthook
        self._IP = IPython.Shell.make_IPython(
                                            argv,user_ns=user_ns,
                                            user_global_ns=user_global_ns,
                                            embedded=True,
                                            shell_class=IPython.Shell.InteractiveShell)

        #we replace IPython default encoding by wx locale encoding
	loc = locale.getpreferredencoding()
	if loc:
        	self._IP.stdin_encoding = loc
        #we replace the ipython default pager by our pager
        self._IP.set_hook('show_in_pager',self._pager)
        
        #we replace the ipython default shell command caller by our shell handler
	self._IP.set_hook('shell_hook',self._shell)
        
        #we replace the ipython default input command caller by our method
        IPython.iplib.raw_input_original = self._raw_input
        #we replace the ipython default exit command by our method
        self._IP.exit = self._setAskExit
            
        sys.excepthook = excepthook

        self._iter_more = 0
        self._history_level = 0
        self._complete_sep =  re.compile('[\s\{\}\[\]\(\)]')
        self._prompt = str(self._IP.outputcache.prompt1).strip()

        #thread working vars
        self._terminate = False
        self._time_loop = time_loop
        self._has_doc = False
        self._do_execute = False
        self._line_to_execute = ''
        self._doc_text = None
        self._ask_exit = False

    #----------------------- Thread management section ----------------------    
    def run (self):
        """
        Thread main loop
        The thread will run until self._terminate will be set to True via shutdown() function
        Command processing can be interrupted with Instance.raise_exc(KeyboardInterrupt) call in the
        GUI thread.
        """
        while(not self._terminate):
            try:
                if self._do_execute:
                    self._doc_text = None
                    self._execute()
                    self._do_execute = False
                
            except KeyboardInterrupt:
                pass

            time.sleep(self._time_loop)
            
    def shutdown(self): 
        """
        Shutdown the tread
        """
        self._terminate = True

    def doExecute(self,line):
        """
        Tell the thread to process the 'line' command
        """
        self._do_execute = True
        self._line_to_execute = line
        
    def isExecuteDone(self):
        """
        Returns the processing state
        """
        return not self._do_execute

    #----------------------- IPython management section ----------------------    
    def getAskExit(self):
        '''
        returns the _ask_exit variable that can be checked by GUI to see if
        IPython request an exit handling
        '''
        return self._ask_exit

    def clearAskExit(self):
        '''
        clear the _ask_exit var when GUI as handled the request.
        '''
        self._ask_exit = False
        
    def getDocText(self):
        """
        Returns the output of the processing that need to be paged (if any)

        @return: The std output string.
        @rtype: string
        """
        return self._doc_text
        
    def getBanner(self):
        """
        Returns the IPython banner for useful info on IPython instance

        @return: The banner string.
        @rtype: string
        """
        return self._IP.BANNER
    
    def getPromptCount(self):
        """
        Returns the prompt number.
        Each time a user execute a line in the IPython shell the prompt count is increased

        @return: The prompt number
        @rtype: int
        """
        return self._IP.outputcache.prompt_count

    def getPrompt(self):
        """
        Returns current prompt inside IPython instance
        (Can be In [...]: ot ...:)

        @return: The current prompt.
        @rtype: string
        """
        return self._prompt

    def getIndentation(self):
        """
        Returns the current indentation level
        Usefull to put the caret at the good start position if we want to do autoindentation.

        @return: The indentation level.
        @rtype: int
        """
        return self._IP.indent_current_nsp
        
    def updateNamespace(self, ns_dict):
        '''
        Add the current dictionary to the shell namespace.

        @param ns_dict: A dictionary of symbol-values.
        @type ns_dict: dictionary
        '''
        self._IP.user_ns.update(ns_dict)

    def complete(self, line):
        '''
        Returns an auto completed line and/or posibilities for completion.

        @param line: Given line so far.
        @type line: string

        @return: Line completed as for as possible,
        and possible further completions.
        @rtype: tuple
        '''
        split_line = self._complete_sep.split(line)
        possibilities = self._IP.complete(split_line[-1])
        if possibilities:

            def _commonPrefix(str1, str2):
                '''
                Reduction function. returns common prefix of two given strings.

                @param str1: First string.
                @type str1: string
                @param str2: Second string
                @type str2: string

                @return: Common prefix to both strings.
                @rtype: string
                '''
                for i in range(len(str1)):
                    if not str2.startswith(str1[:i+1]):
                        return str1[:i]
                return str1
            common_prefix = reduce(_commonPrefix, possibilities)
            completed = line[:-len(split_line[-1])]+common_prefix
        else:
            completed = line
        return completed, possibilities

    def historyBack(self):
        '''
        Provides one history command back.

        @return: The command string.
        @rtype: string
        '''
        history = ''
        #the below while loop is used to suppress empty history lines
	while((history == '' or history == '\n') and self._history_level >0):
		if self._history_level>=1:
			self._history_level -= 1
		history = self._getHistory()		
        return history

    def historyForward(self):
        '''
        Provides one history command forward.

        @return: The command string.
        @rtype: string
        '''
	history = ''
	#the below while loop is used to suppress empty history lines
	while((history == '' or history == '\n') and self._history_level <= self._getHistoryMaxIndex()):
		if self._history_level < self._getHistoryMaxIndex():
			self._history_level += 1
			history = self._getHistory()
		else:
			if self._history_level == self._getHistoryMaxIndex():
				history = self._getHistory()
				self._history_level += 1
			else:
				history = ''
        return history

    def initHistoryIndex(self):
        '''
        set history to last command entered
        '''
        self._history_level = self._getHistoryMaxIndex()+1

    #----------------------- IPython PRIVATE management section ----------------------    
    def _setAskExit(self):
        '''
        set the _ask_exit variable that can be cjhecked by GUI to see if
        IPython request an exit handling
        '''
        self._ask_exit = True
        
    def _getHistoryMaxIndex(self):
        '''
        returns the max length of the history buffer

        @return: history length
        @rtype: int
        '''
        return len(self._IP.input_hist_raw)-1
        
    def _getHistory(self):
        '''
        Get's the command string of the current history level.

        @return: Historic command string.
        @rtype: string
        '''
        rv = self._IP.input_hist_raw[self._history_level].strip('\n')
        return rv

    def _pager(self,IP,text):
        '''
        This function is used as a callback replacment to IPython pager function

        It puts the 'text' value inside the self._doc_text string that can be retrived via getDocText
        function.
        '''
        self._doc_text = text
    
    def _raw_input(self, prompt=''):
        '''
        Custom raw_input() replacement. Get's current line from console buffer.

        @param prompt: Prompt to print. Here for compatability as replacement.
        @type prompt: string

        @return: The current command line text.
        @rtype: string
        '''
        return self._line_to_execute

    def _execute(self):
        '''
        Executes the current line provided by the shell object.
        '''
        orig_stdout = sys.stdout
        sys.stdout = IPython.Shell.Term.cout
                
        try:
            line = self._IP.raw_input(None, self._iter_more)
            if self._IP.autoindent:
                self._IP.readline_startup_hook(None)

        except KeyboardInterrupt:
            self._IP.write('\nKeyboardInterrupt\n')
            self._IP.resetbuffer()
            # keep cache in sync with the prompt counter:
            self._IP.outputcache.prompt_count -= 1

            if self._IP.autoindent:
                self._IP.indent_current_nsp = 0
            self._iter_more = 0
        except:
            self._IP.showtraceback()
        else:
            self._iter_more = self._IP.push(line)
            if (self._IP.SyntaxTB.last_syntax_error and
                    self._IP.rc.autoedit_syntax):
                self._IP.edit_syntax_error()
        if self._iter_more:
            self._prompt = str(self._IP.outputcache.prompt2).strip()
            if self._IP.autoindent:
                self._IP.readline_startup_hook(self._IP.pre_readline)
        else:
            self._prompt = str(self._IP.outputcache.prompt1).strip()
            self._IP.indent_current_nsp = 0 #we set indentation to 0
        sys.stdout = orig_stdout
    
    def _shell(self, ip, cmd):
        '''
        Replacement method to allow shell commands without them blocking.

        @param ip: Ipython instance, same as self._IP
        @type cmd: Ipython instance
        @param cmd: Shell command to execute.
        @type cmd: string
        '''
        stdin, stdout = os.popen4(cmd)
        result = stdout.read().decode('cp437').encode(locale.getpreferredencoding())
        #we use print command because the shell command is called inside IPython instance and thus is
        #redirected to thread cout
        #"\x01\x1b[1;36m\x02" <-- add colour to the text...
        print "\x01\x1b[1;36m\x02"+result
        stdout.close()
        stdin.close()

class WxConsoleView(stc.StyledTextCtrl):
    '''
    Specialized styled text control view for console-like workflow.
    We use here a scintilla frontend thus it can be reused in any GUI taht supports
    scintilla with less work.

    @cvar ANSI_COLORS_BLACK: Mapping of terminal colors to X11 names.(with Black background)
    @type ANSI_COLORS_BLACK: dictionary

    @cvar ANSI_COLORS_WHITE: Mapping of terminal colors to X11 names.(with White background)
    @type ANSI_COLORS_WHITE: dictionary

    @ivar color_pat: Regex of terminal color pattern
    @type color_pat: _sre.SRE_Pattern
    '''
    ANSI_STYLES_BLACK ={'0;30': [0,'WHITE'],             '0;31': [1,'RED'],
                        '0;32': [2,'GREEN'],             '0;33': [3,'BROWN'],
                        '0;34': [4,'BLUE'],              '0;35': [5,'PURPLE'],
                        '0;36': [6,'CYAN'],              '0;37': [7,'LIGHT GREY'],
                        '1;30': [8,'DARK GREY'],         '1;31': [9,'RED'],
                        '1;32': [10,'SEA GREEN'],        '1;33': [11,'YELLOW'],
                        '1;34': [12,'LIGHT BLUE'],       '1;35': [13,'MEDIUM VIOLET RED'],
                        '1;36': [14,'LIGHT STEEL BLUE'], '1;37': [15,'YELLOW']}

    ANSI_STYLES_WHITE ={'0;30': [0,'BLACK'],             '0;31': [1,'RED'],
                        '0;32': [2,'GREEN'],             '0;33': [3,'BROWN'],
                        '0;34': [4,'BLUE'],              '0;35': [5,'PURPLE'],
                        '0;36': [6,'CYAN'],              '0;37': [7,'LIGHT GREY'],
                        '1;30': [8,'DARK GREY'],         '1;31': [9,'RED'],
                        '1;32': [10,'SEA GREEN'],        '1;33': [11,'YELLOW'],
                        '1;34': [12,'LIGHT BLUE'],       '1;35': [13,'MEDIUM VIOLET RED'],
                        '1;36': [14,'LIGHT STEEL BLUE'], '1;37': [15,'YELLOW']}

    def __init__(self,parent,prompt,intro="",background_color="BLACK",pos=wx.DefaultPosition, ID = -1, size=wx.DefaultSize,
                 style=0):
        '''
        Initialize console view.

        @param parent: Parent widget
        @param prompt: User specified prompt
        @type intro: string
        @param intro: User specified startup introduction string
        @type intro: string
        @param background_color: Can be BLACK or WHITE
        @type background_color: string
        @param other: init param of styledTextControl (can be used as-is)
        '''
        stc.StyledTextCtrl.__init__(self, parent, ID, pos, size, style)

        ####### Scintilla configuration ##################################################
        
        # Ctrl + B or Ctrl + N can be used to zoomin/zoomout the text inside the widget
        self.CmdKeyAssign(ord('B'), stc.STC_SCMOD_CTRL, stc.STC_CMD_ZOOMIN)
        self.CmdKeyAssign(ord('N'), stc.STC_SCMOD_CTRL, stc.STC_CMD_ZOOMOUT)

        #we define platform specific fonts
        if wx.Platform == '__WXMSW__':
                faces = { 'times': 'Times New Roman',
                          'mono' : 'Courier New',
                          'helv' : 'Arial',
                          'other': 'Comic Sans MS',
                          'size' : 10,
                          'size2': 8,
                         }
        elif wx.Platform == '__WXMAC__':
            faces = { 'times': 'Times New Roman',
                      'mono' : 'Monaco',
                      'helv' : 'Arial',
                      'other': 'Comic Sans MS',
                      'size' : 10,
                      'size2': 8,
                     }
        else:
            faces = { 'times': 'Times',
                      'mono' : 'Courier',
                      'helv' : 'Helvetica',
                      'other': 'new century schoolbook',
                      'size' : 10,
                      'size2': 8,
                     }

        #We draw a line at position 80
        self.SetEdgeMode(stc.STC_EDGE_LINE)
        self.SetEdgeColumn(80)
        self.SetEdgeColour(wx.LIGHT_GREY)

        #self.SetViewWhiteSpace(True)
        #self.SetViewEOL(True)
        self.SetEOLMode(stc.STC_EOL_CRLF)
        #self.SetWrapMode(stc.STC_WRAP_CHAR)
        #self.SetWrapMode(stc.STC_WRAP_WORD)
        self.SetBufferedDraw(True)
        #self.SetUseAntiAliasing(True)
        self.SetLayoutCache(stc.STC_CACHE_PAGE)

        self.EnsureCaretVisible()
        
        self.SetMargins(3,3) #text is moved away from border with 3px
        # Suppressing Scintilla margins
        self.SetMarginWidth(0,0)
        self.SetMarginWidth(1,0)
        self.SetMarginWidth(2,0)

        # make some styles
        if background_color != "BLACK":
            self.background_color = "WHITE"
            self.SetCaretForeground("BLACK")
            self.ANSI_STYLES = self.ANSI_STYLES_WHITE
        else:
            self.background_color = background_color
            self.SetCaretForeground("WHITE")
            self.ANSI_STYLES = self.ANSI_STYLES_BLACK

        self.StyleSetSpec(stc.STC_STYLE_DEFAULT, "fore:%s,back:%s,size:%d,face:%s" % (self.ANSI_STYLES['0;30'][1],
                                                                                      self.background_color,
                                                                                      faces['size'], faces['mono']))
        self.StyleClearAll()
        self.StyleSetSpec(stc.STC_STYLE_BRACELIGHT,  "fore:#FF0000,back:#0000FF,bold")
        self.StyleSetSpec(stc.STC_STYLE_BRACEBAD,    "fore:#000000,back:#FF0000,bold")
    
        for style in self.ANSI_STYLES.values():
            self.StyleSetSpec(style[0], "bold,fore:%s" % style[1])
        
        #######################################################################
        
        self.indent = 0
        self.prompt_count = 0
        self.color_pat = re.compile('\x01?\x1b\[(.*?)m\x02?')
        
        self.write(intro)
        self.setPrompt(prompt)
        self.showPrompt()
        
        self.Bind(wx.EVT_KEY_DOWN, self._onKeypress, self)
        #self.Bind(stc.EVT_STC_UPDATEUI, self.OnUpdateUI)

    def write(self, text):
        '''
        Write given text to buffer.

        @param text: Text to append.
        @type text: string
        '''
        segments = self.color_pat.split(text)
        segment = segments.pop(0)
        self.StartStyling(self.getCurrentLineEnd(),0xFF)
        self.AppendText(segment)
        
        if segments:
            ansi_tags = self.color_pat.findall(text)

            for tag in ansi_tags:
                i = segments.index(tag)
                self.StartStyling(self.getCurrentLineEnd(),0xFF)
                self.AppendText(segments[i+1])

                if tag != '0':
                    self.SetStyling(len(segments[i+1]),self.ANSI_STYLES[tag][0])

                segments.pop(i)
                
        self.moveCursor(self.getCurrentLineEnd())
         
    def getPromptLen(self):
        '''
        Return the length of current prompt
        '''
        return len(str(self.prompt_count)) + 7

    def setPrompt(self,prompt):
        self.prompt = prompt

    def setIndentation(self,indentation):
        self.indent = indentation
        
    def setPromptCount(self,count):
        self.prompt_count = count
        
    def showPrompt(self):
        '''
        Prints prompt at start of line.

        @param prompt: Prompt to print.
        @type prompt: string
        '''
        self.write(self.prompt)
        #now we update the position of end of prompt
        self.current_start = self.getCurrentLineEnd()
        
        autoindent = self.indent*' '
        autoindent = autoindent.replace('    ','\t')
        self.write(autoindent)
        
    def changeLine(self, text):
        '''
        Replace currently entered command line with given text.

        @param text: Text to use as replacement.
        @type text: string
        '''
        self.SetSelection(self.getCurrentPromptStart(),self.getCurrentLineEnd())
        self.ReplaceSelection(text)
        self.moveCursor(self.getCurrentLineEnd())

    def getCurrentPromptStart(self):
        return self.current_start

    def getCurrentLineStart(self):
        return self.GotoLine(self.LineFromPosition(self.GetCurrentPos()))

    def getCurrentLineEnd(self):
        return self.GetLength()

    def getCurrentLine(self):
        '''
        Get text in current command line.

        @return: Text of current command line.
        @rtype: string
        '''
        return self.GetTextRange(self.getCurrentPromptStart(),
                                 self.getCurrentLineEnd())

    def showReturned(self, text):
        '''
        Show returned text from last command and print new prompt.

        @param text: Text to show.
        @type text: string
        '''
        self.write('\n'+text)
        if text:
            self.write('\n')
        self.showPrompt()

    def moveCursorOnNewValidKey(self):
        #If cursor is at wrong position put it at last line...
        if self.GetCurrentPos() < self.getCurrentPromptStart():
            self.GotoPos(self.getCurrentPromptStart())
        
    def removeFromTo(self,from_pos,to_pos):
        if from_pos < to_pos:
            self.SetSelection(from_pos,to_pos)
            self.DeleteBack()
                                                          
    def removeCurrentLine(self):
        self.LineDelete()
        
    def moveCursor(self,position):
        self.GotoPos(position)

    def getCursorPos(self):
        return self.GetCurrentPos()

    def selectFromTo(self,from_pos,to_pos):
        self.SetSelectionStart(from_pos)
        self.SetSelectionEnd(to_pos)
        
    def writeHistory(self,history):
        self.removeFromTo(self.getCurrentPromptStart(),self.getCurrentLineEnd())
        self.changeLine(history)
        
    def writeCompletion(self, possibilities):
        max_len = len(max(possibilities,key=len))
        max_symbol =' '*max_len
        
        #now we check how much symbol we can put on a line...
        cursor_pos = self.getCursorPos()
        test_buffer = max_symbol + ' '*4
        current_lines = self.GetLineCount()
        
        allowed_symbols = 80/len(test_buffer)
        if allowed_symbols == 0:
                allowed_symbols = 1
        
        pos = 1
        buf = ''
        for symbol in possibilities:
            #buf += symbol+'\n'#*spaces)
            if pos<allowed_symbols:
                spaces = max_len - len(symbol) + 4
                buf += symbol+' '*spaces
                pos += 1
            else:
                buf+=symbol+'\n'
                pos = 1
        self.write(buf)
                             
    def _onKeypress(self, event, skip=True):
        '''
        Key press callback used for correcting behavior for console-like
        interfaces. For example 'home' should go to prompt, not to begining of
        line.

        @param widget: Widget that key press accored in.
        @type widget: gtk.Widget
        @param event: Event object
        @type event: gtk.gdk.Event

        @return: Return True if event as been catched.
        @rtype: boolean
        '''
	
        if event.GetKeyCode() == wx.WXK_HOME:
            if event.Modifiers == wx.MOD_NONE:
                self.moveCursorOnNewValidKey()
                self.moveCursor(self.getCurrentPromptStart())
                return True
            elif event.Modifiers == wx.MOD_SHIFT:
                self.moveCursorOnNewValidKey()
                self.selectFromTo(self.getCurrentPromptStart(),self.getCursorPos())
                return True
            else:
                return False

        elif event.GetKeyCode() == wx.WXK_LEFT:
            if event.Modifiers == wx.MOD_NONE:
                self.moveCursorOnNewValidKey()
                
                self.moveCursor(self.getCursorPos()-1)
                if self.getCursorPos() < self.getCurrentPromptStart():
                    self.moveCursor(self.getCurrentPromptStart())
                return True

        elif event.GetKeyCode() == wx.WXK_BACK:
            self.moveCursorOnNewValidKey()
	    if self.getCursorPos() > self.getCurrentPromptStart():
                self.removeFromTo(self.getCursorPos()-1,self.getCursorPos())
	    return True
        
        if skip:
            if event.GetKeyCode() not in [wx.WXK_PAGEUP,wx.WXK_PAGEDOWN] and event.Modifiers == wx.MOD_NONE:
                self.moveCursorOnNewValidKey()
                
            event.Skip()
            return True
        return False

    def OnUpdateUI(self, evt):
        # check for matching braces
        braceAtCaret = -1
        braceOpposite = -1
        charBefore = None
        caretPos = self.GetCurrentPos()

        if caretPos > 0:
            charBefore = self.GetCharAt(caretPos - 1)
            styleBefore = self.GetStyleAt(caretPos - 1)

        # check before
        if charBefore and chr(charBefore) in "[]{}()" and styleBefore == stc.STC_P_OPERATOR:
            braceAtCaret = caretPos - 1

        # check after
        if braceAtCaret < 0:
            charAfter = self.GetCharAt(caretPos)
            styleAfter = self.GetStyleAt(caretPos)

            if charAfter and chr(charAfter) in "[]{}()" and styleAfter == stc.STC_P_OPERATOR:
                braceAtCaret = caretPos

        if braceAtCaret >= 0:
            braceOpposite = self.BraceMatch(braceAtCaret)

        if braceAtCaret != -1  and braceOpposite == -1:
            self.BraceBadLight(braceAtCaret)
        else:
            self.BraceHighlight(braceAtCaret, braceOpposite)
            #pt = self.PointFromPosition(braceOpposite)
            #self.Refresh(True, wxRect(pt.x, pt.y, 5,5))
            #print pt
            #self.Refresh(False)
        
class WxIPythonViewPanel(wx.Panel):
    '''
    This is wx.Panel that embbed the IPython Thread and the wx.StyledTextControl
    If you want to port this to any other GUI toolkit, just replace the WxConsoleView
    by YOURGUIConsoleView and make YOURGUIIPythonView derivate from whatever container you want.
    I've choosed to derivate from a wx.Panel because it seems to be ore usefull
    Any idea to make it more 'genric' welcomed.
    '''
    def __init__(self,parent,exit_handler=None,intro=None,background_color="BLACK"):
        '''
        Initialize.
        Instanciate an IPython thread.
        Instanciate a WxConsoleView.
        Redirect I/O to console.
        '''
        wx.Panel.__init__(self,parent,-1)

        ### IPython thread instanciation ###
        self.cout = StringIO()
        self.IP = IterableIPShell(cout=self.cout,cerr=self.cout,
                             exit_handler = exit_handler,
                             time_loop = 0.1)
        self.IP.start()
        
        ### IPython wx console view instanciation ###
        #If user didn't defined an intro text, we create one for him
        #If you really wnat an empty intrp just call wxIPythonViewPanel with intro=''
        if intro == None:
            welcome_text = "Welcome to WxIPython Shell.\n\n"
            welcome_text+= self.IP.getBanner()
            welcome_text+= "!command  -> Execute command in shell\n"
            welcome_text+= "TAB       -> Autocompletion\n"

        self.text_ctrl = WxConsoleView(self,
                                       self.IP.getPrompt(),
                                       intro=welcome_text,
                                       background_color=background_color)
        
        self.text_ctrl.Bind(wx.EVT_KEY_DOWN, self.keyPress, self.text_ctrl)

        ### making the layout of the panel ###
        sizer = wx.BoxSizer(wx.VERTICAL)
        sizer.Add(self.text_ctrl, 1, wx.EXPAND)
        self.SetAutoLayout(True)
        sizer.Fit(self)
        sizer.SetSizeHints(self)
        self.SetSizer(sizer)
        #and we focus on the widget :)
        self.SetFocus()

        ### below are the thread communication variable ###
        # the IPython thread is managed via unidirectional communication.
        # It's a thread slave that can't interact by itself with the GUI.
        # When the GUI event loop is done runStateMachine() is called and the thread sate is then
        # managed.
        
        #Initialize the state machine #kept for information
        #self.states = ['IDLE',
        #               'DO_EXECUTE_LINE',
        #               'WAIT_END_OF_EXECUTION',
        #               'SHOW_DOC',
        #               'SHOW_PROMPT']
        
        self.cur_state = 'IDLE'
	self.pager_state = 'DONE'
        #wx.CallAfter(self.runStateMachine)

        # This creates a new Event class and a EVT binder function
        (self.AskExitEvent, EVT_ASK_EXIT) = wx.lib.newevent.NewEvent()

        self.Bind(wx.EVT_IDLE, self.runStateMachine)
        self.Bind(EVT_ASK_EXIT, exit_handler)
        
    def __del__(self):
        self.IP.shutdown()
        self.IP.join()
        WxConsoleView.__del__()
        
    #---------------------------- IPython Thread Management ---------------------------------------
    def runStateMachine(self,event):
        #print >>self.sys_stdout,"state:",self.cur_state
        self.updateStatusTracker(self.cur_state)
        
        if self.cur_state == 'DO_EXECUTE_LINE':
            #print >>self.sys_stdout,"command:",self.getCurrentLine()
            self.IP.doExecute(self.text_ctrl.getCurrentLine().replace('\t',' '*4))
            self.updateHistoryTracker(self.text_ctrl.getCurrentLine())
            self.cur_state = 'WAIT_END_OF_EXECUTION'
        
        if self.cur_state == 'WAIT_END_OF_EXECUTION':
            if self.IP.isExecuteDone():
                self.doc = self.IP.getDocText()
                if self.IP.getAskExit():
                    evt = self.AskExitEvent()
                    wx.PostEvent(self, evt)
                    self.IP.clearAskExit()
                if self.doc:
                    self.pager_state = 'INIT'
		    self.cur_state = 'SHOW_DOC'
                else:
                    self.cur_state = 'SHOW_PROMPT'
                
        if self.cur_state == 'SHOW_PROMPT':
            self.text_ctrl.setPrompt(self.IP.getPrompt())
            self.text_ctrl.setIndentation(self.IP.getIndentation())
            self.text_ctrl.setPromptCount(self.IP.getPromptCount())
            rv = self.cout.getvalue()
            if rv: rv = rv.strip('\n')
            self.text_ctrl.showReturned(rv)
            self.cout.truncate(0)
	    self.IP.initHistoryIndex()
            self.cur_state = 'IDLE'
            
        if self.cur_state == 'SHOW_DOC':
            self.pager(self.doc)
            if self.pager_state == 'DONE':
                self.cur_state = 'SHOW_PROMPT'
                
        event.Skip()

    #---------------------------- IPython pager ---------------------------------------
    def pager(self,text):#,start=0,screen_lines=0,pager_cmd = None):
        if self.pager_state == 'WAITING':
		#print >>self.sys_stdout,"PAGER waiting"
        	return
	
	if self.pager_state == 'INIT':
		#print >>self.sys_stdout,"PAGER state:",self.pager_state
        	self.pager_lines = text[7:].split('\n')
		self.pager_nb_lines = len(self.pager_lines)
		self.pager_index = 0
		self.pager_do_remove = False
		self.text_ctrl.write('\n')
		self.pager_state = 'PROCESS_LINES'
		
	if self.pager_state == 'PROCESS_LINES':
        	#print >>self.sys_stdout,"PAGER state:",self.pager_state
        	if self.pager_do_remove == True:
			self.text_ctrl.removeCurrentLine()
			self.pager_do_remove = False
	
		if self.pager_nb_lines > 10:
	                #print >>self.sys_stdout,"PAGER processing 10 lines"
			if self.pager_index > 0:
				self.text_ctrl.write(">\x01\x1b[1;36m\x02"+self.pager_lines[self.pager_index]+'\n')
			else:
				self.text_ctrl.write("\x01\x1b[1;36m\x02 "+self.pager_lines[self.pager_index]+'\n')
			
			for line in self.pager_lines[self.pager_index+1:self.pager_index+9]:
				self.text_ctrl.write("\x01\x1b[1;36m\x02 "+line+'\n')
			self.pager_index += 10
			self.pager_nb_lines -= 10
			self.text_ctrl.write("--- Push Enter to continue or 'Q' to quit---")
			self.pager_do_remove = True
			self.pager_state = 'WAITING'
			return
        	else:
	                #print >>self.sys_stdout,"PAGER processing last lines"
			if self.pager_nb_lines > 0:
				if self.pager_index > 0:
					self.text_ctrl.write(">\x01\x1b[1;36m\x02"+self.pager_lines[self.pager_index]+'\n')
				else:
					self.text_ctrl.write("\x01\x1b[1;36m\x02 "+self.pager_lines[self.pager_index]+'\n')
				
				self.pager_index += 1
                                self.pager_nb_lines -= 1
	              	if self.pager_nb_lines > 0:
        	        	for line in self.pager_lines[self.pager_index:]:
					self.text_ctrl.write("\x01\x1b[1;36m\x02 "+line+'\n')
                			self.pager_nb_lines = 0
			self.pager_state = 'DONE'          
                
    #---------------------------- Key Handler --------------------------------------------
    def keyPress(self, event):
        '''
        Key press callback with plenty of shell goodness, like history,
        autocompletions, etc.
        '''
	
        if event.GetKeyCode() == ord('C'):
            if event.Modifiers == wx.MOD_CONTROL:
                if self.cur_state == 'WAIT_END_OF_EXECUTION':
                    #we raise an exception inside the IPython thread container
                    self.IP.raise_exc(KeyboardInterrupt)
                    return
                
        if event.KeyCode == wx.WXK_RETURN:
            if self.cur_state == 'IDLE':
                #we change the state ot the state machine
                self.cur_state = 'DO_EXECUTE_LINE'
                return
            if self.pager_state == 'WAITING':
                self.pager_state = 'PROCESS_LINES'
                return
            
        if event.GetKeyCode() in [ord('q'),ord('Q')]:
            if self.pager_state == 'WAITING':
                self.pager_state = 'DONE'
                return
            
        #scroll_position = self.text_ctrl.GetScrollPos(wx.VERTICAL)
	if self.cur_state == 'IDLE':
            if event.KeyCode == wx.WXK_UP:
                history = self.IP.historyBack()
                self.text_ctrl.writeHistory(history)
                return
            if event.KeyCode == wx.WXK_DOWN:
                history = self.IP.historyForward()
                self.text_ctrl.writeHistory(history)
                return
            if event.KeyCode == wx.WXK_TAB:
                #if line empty we disable tab completion
                if not self.text_ctrl.getCurrentLine().strip():
                    self.text_ctrl.write('\t')
                    return
                completed, possibilities = self.IP.complete(self.text_ctrl.getCurrentLine())
                if len(possibilities) > 1:
                    cur_slice = self.text_ctrl.getCurrentLine()
                    self.text_ctrl.write('\n')
                    self.text_ctrl.writeCompletion(possibilities)
                    self.text_ctrl.write('\n')

                    self.text_ctrl.showPrompt()
                    self.text_ctrl.write(cur_slice)
                self.text_ctrl.changeLine(completed or cur_slice)
                
                return
            event.Skip()
	
    #---------------------------- Hook Section --------------------------------------------
    def updateHistoryTracker(self,command_line):
        '''
        Default history tracker (does nothing)
        '''
        pass
    
    def setHistoryTrackerHook(self,func):
        '''
        Define a new history tracker
        '''
        self.updateHistoryTracker = func
    def updateStatusTracker(self,status):
        '''
        Default status tracker (does nothing)
        '''
        pass
    
    def setStatusTrackerHook(self,func):
        '''
        Define a new status tracker
        '''
        self.updateStatusTracker = func