From c2fab0bd95fbd840d353c1753c730bd27f1ea6c2 2009-03-30 00:15:21
From: Gael Varoquaux <gael.varoquaux@normalesup.org>
Date: 2009-03-30 00:15:21
Subject: [PATCH] ENH: Backspace now deletes continuation lines
---

diff --git a/IPython/frontend/wx/console_widget.py b/IPython/frontend/wx/console_widget.py
index c63bc19..35c2d9c 100644
--- a/IPython/frontend/wx/console_widget.py
+++ b/IPython/frontend/wx/console_widget.py
@@ -242,7 +242,9 @@ class ConsoleWidget(editwindow.EditWindow):
 
 
     def continuation_prompt(self):
-        """Returns the current continuation prompt.
+        """ Returns the current continuation prompt.
+            We need to implement this method here to deal with the
+            ascii escape sequences cleaning up.
         """
         # ASCII-less prompt
         ascii_less = ''.join(self.color_pat.split(self.last_prompt)[2::2])
@@ -271,21 +273,6 @@ class ConsoleWidget(editwindow.EditWindow):
         return self.GetSize()[0]/self.GetCharWidth()
 
 
-
-    #--------------------------------------------------------------------------
-    # EditWindow API
-    #--------------------------------------------------------------------------
-
-    def OnUpdateUI(self, event):
-        """ Override the OnUpdateUI of the EditWindow class, to prevent 
-            syntax highlighting both for faster redraw, and for more
-            consistent look and feel.
-        """
-
-    #--------------------------------------------------------------------------
-    # Styling API
-    #--------------------------------------------------------------------------
-
     def configure_scintilla(self):
 
         p = self.style
@@ -461,7 +448,18 @@ class ConsoleWidget(editwindow.EditWindow):
                 self.SetEdgeMode(stc.STC_EDGE_LINE)
                 self.SetEdgeColumn(88)
  
-        
+ 
+    #--------------------------------------------------------------------------
+    # EditWindow API
+    #--------------------------------------------------------------------------
+
+    def OnUpdateUI(self, event):
+        """ Override the OnUpdateUI of the EditWindow class, to prevent 
+            syntax highlighting both for faster redraw, and for more
+            consistent look and feel.
+        """
+
+       
     #--------------------------------------------------------------------------
     # Private API
     #--------------------------------------------------------------------------
@@ -572,6 +570,7 @@ class ConsoleWidget(editwindow.EditWindow):
         self._keep_cursor_in_buffer()
 
 
+    # XXX:  I need to avoid the problem of having an empty glass;
     def _keep_cursor_in_buffer(self, pos=None):
         """ Checks if the cursor is where it is allowed to be. If not,
             put it back.
@@ -602,7 +601,7 @@ class ConsoleWidget(editwindow.EditWindow):
         # Jump the continuation prompt
         continuation_prompt = self.continuation_prompt()
         if ( line.startswith(continuation_prompt)
-                     and line_pos < len(continuation_prompt)+1):
+                     and line_pos < len(continuation_prompt)):
             if line_pos < 2:
                 # We are at the beginning of the line, trying to move
                 # forward: jump forward.
diff --git a/IPython/frontend/wx/wx_frontend.py b/IPython/frontend/wx/wx_frontend.py
index cdb6742..e6745d5 100644
--- a/IPython/frontend/wx/wx_frontend.py
+++ b/IPython/frontend/wx/wx_frontend.py
@@ -459,8 +459,36 @@ class WxController(ConsoleWidget, PrefilterFrontEnd):
                         wx.CallAfter(self._popup_completion, create=True)
                 else:
                     event.Skip()
+            elif event.KeyCode == wx.WXK_BACK:
+                # If characters where erased, check if we have to
+                # remove a line.
+                # XXX: What about DEL?
+                current_line, _ = self.CurLine
+                current_pos = self.GetCurrentPos()
+                current_line_number = self.LineFromPosition(current_pos)
+                current_col = self.GetColumn(current_pos)
+                len_prompt = len(self.continuation_prompt())
+                if ( current_line.startswith(self.continuation_prompt())
+                        and current_col == len_prompt):
+                    print 'BACK', current_line, self.current_prompt_line, \
+                            current_line_number
+                    new_lines = []
+                    for line_num, line in enumerate(
+                                    self.input_buffer.split('\n')):
+                        if (line_num + self.current_prompt_line ==
+                                            current_line_number):
+                            new_lines.append(line[len_prompt:])
+                        else:
+                            new_lines.append('\n'+line)
+                    # The first character is '\n', due to the above
+                    # code:
+                    self.input_buffer = ''.join(new_lines)[1:]
+                    self.GotoPos(current_pos - 1 - len_prompt)
+                else:
+                    ConsoleWidget._on_key_down(self, event, skip=skip)
             else:
                 ConsoleWidget._on_key_down(self, event, skip=skip)
+                        
 
 
     def _on_key_up(self, event, skip=True):
@@ -472,11 +500,15 @@ class WxController(ConsoleWidget, PrefilterFrontEnd):
             wx.CallAfter(self._popup_completion, create=True)
         else:
             ConsoleWidget._on_key_up(self, event, skip=skip)
-        if (self.input_buffer.split('\n')[-1] == self.continuation_prompt()
-                        and self._input_state == 'readline'):
-            # Make sure the continuation_prompt is followed by a whitespace
+        # Make sure the continuation_prompts are always followed by a 
+        # whitespace
+        new_lines = []
+        if self._input_state == 'readline':
             position = self.GetCurrentPos()
-            self.input_buffer += ' '
+            for line in self.input_buffer.split('\n'):
+                if not line == self.continuation_prompt()[:-1]:
+                    new_lines.append(line)
+            self.input_buffer = '\n'.join(new_lines)
             self.GotoPos(position)