Comprehensively use 'is None' and 'is not None'

Use 'is None' and 'is not None' everywhere; this was recommended
by Jonathan Griffitts in http://www.reinteract.org/trac/ticket/71.
Going ahead and doing it now was inspired by the xmlrpc horror
in http://www.reinteract.org/trac/ticket/77.

No Reinteract object will ever be badly behaved enough to try and
make a remote procedure call when its __eq__() method is called,
but it's easier to make a blanket search and replace than audit
everywhere for user-supplied objects.

lib/reinteract/about_dialog.py

@@ -32,7 +32,7 @@ def _find_url_open_program():
 
     for progname in ['xdg-open', 'htmlview', 'gnome-open']:
         path = _find_program_in_path(progname)
-        if path != None:
+        if path is not None:
             return path
     return None
 
@@ -42,7 +42,7 @@ def _open_url(dialog, url):
 
 class AboutDialog(gtk.AboutDialog):
     def __init__(self):
-        if _find_url_open_program() != None:
+        if _find_url_open_program() is not None:
             gtk.about_dialog_set_url_hook(_open_url)
 
         gtk.AboutDialog.__init__(self)

lib/reinteract/application.py

@@ -124,7 +124,7 @@ def find_notebook_path(self, path):
                     return None, None
 
             tmp = parent
-            if relative == None:
+            if relative is None:
                 relative = basename
             else:
                 relative = os.path.join(basename, relative)
@@ -163,7 +163,7 @@ def open_path(self, path):
     def create_notebook(self, path, description=None):
         os.makedirs(path)
         notebook = Notebook(path)
-        if description != None:
+        if description is not None:
             notebook.info.description = description
         window = self.__make_notebook_window(notebook)
         window.show()

lib/reinteract/base_notebook_window.py

@@ -57,16 +57,16 @@ def __init__(self, notebook):
             self.open_file(file)
 
         current_file_editor = None
-        if current_file != None:
+        if current_file is not None:
             filename = os.path.join(notebook.folder, current_file)
             for editor in self.editors:
                 if editor.filename == filename:
                     current_file_editor = editor
 
-        if current_file_editor == None and len(self.editors) > 0:
+        if current_file_editor is None and len(self.editors) > 0:
             current_file_editor = self.editors[0]
 
-        if current_file_editor != None:
+        if current_file_editor is not None:
             self._make_editor_current(current_file_editor)
             current_file_editor.view.grab_focus()
 
@@ -199,7 +199,7 @@ def _update_open_files(self):
 
     def _update_current_file(self):
         file = self.current_editor.file
-        if file != None:
+        if file is not None:
             self.state.set_current_file(file.path)
         else:
             self.state.set_current_file(None)

lib/reinteract/base_window.py

@@ -170,7 +170,7 @@ def on_open(self, action):
         if response == gtk.RESPONSE_OK:
             filename = chooser.get_filename()
 
-        if filename != None:
+        if filename is not None:
             application.open_path(filename)
 
         chooser.destroy()
@@ -265,9 +265,9 @@ def show(self):
         self.window.show()
 
     def update_sensitivity(self):
-        self._set_action_sensitive('calculate', self.current_editor != None and self.current_editor.needs_calculate)
-        self._set_action_sensitive('break', self.current_editor != None and self.current_editor.state == NotebookFile.EXECUTING)
+        self._set_action_sensitive('calculate', self.current_editor is not None and self.current_editor.needs_calculate)
+        self._set_action_sensitive('break', self.current_editor is not None and self.current_editor.state == NotebookFile.EXECUTING)
 
         # This seems more annoying than useful. gedit doesn't desensitize save
-        # self._set_action_sensitive('save', self.current_editor != None and self.current_editor.modified)
+        # self._set_action_sensitive('save', self.current_editor is not None and self.current_editor.modified)
 

lib/reinteract/chunks.py

@@ -96,7 +96,7 @@ def __repr__(self):
 
     def set_lines(self, lines):
         range = self.tokenized.set_lines(lines)
-        if range == None:
+        if range is None:
             return False
 
         if range[0] != range[1]: # non-empty range ... empty=truncation
@@ -112,7 +112,7 @@ def set_lines(self, lines):
         return True
 
     def mark_for_execute(self):
-        if self.statement != None and not self.needs_execute:
+        if self.statement is not None and not self.needs_execute:
             self.statement.mark_for_execute()
             self.needs_execute = True
             self.status_changed = True

lib/reinteract/completion_popup.py

@@ -79,7 +79,7 @@ def __update_completions(self, spontaneous=False):
         self.__in_change = True
         self.__tree_model.clear()
         line, offset = buf.iter_to_pos(buf.get_iter_at_mark(buf.get_insert()), adjust=ADJUST_NONE)
-        if line == None:
+        if line is None:
             completions = []
         else:
             if spontaneous:
@@ -117,7 +117,7 @@ def __update_doc_popup(self):
         # object, but it's distracting to show the class docs on int
         # for every integer constant, etc, which is what the DocPopup
         # does currently.
-        if (obj == None or is_data_object(obj)):
+        if (obj is None or is_data_object(obj)):
             self.__doc_popup.popdown()
             return
 

lib/reinteract/custom_result.py

@@ -39,7 +39,7 @@ def on_activate(menu):
 
         chooser.destroy()
 
-        if filename != None:
+        if filename is not None:
             save_callback(filename)
 
     menu_item.connect('activate', on_activate)

lib/reinteract/data_format.py

@@ -60,7 +60,7 @@ def __format_separate(sequence, open, close, nl):
     lines = 1
     last_str, last_lines = None, 0
     for str, item_lines in sequence:
-        if last_str != None:
+        if last_str is not None:
             # Process the last item, we'll have one more after it
             new_lines = lines + last_lines
 
@@ -79,7 +79,7 @@ def __format_separate(sequence, open, close, nl):
         last_str = str
         last_lines = item_lines
 
-    if last_str != None:
+    if last_str is not None:
         buf.write(last_str)
 
     buf.write(close)
@@ -105,7 +105,7 @@ def __format_wrapped(sequence, open, close, nl):
         if len(str) > _MAX_WRAPPED_ITEM_LEN:
             return None
 
-        if last_str != None:
+        if last_str is not None:
             # Process the last item, we'll have one more after it
             new_available_width = available_width - (len(last_str) + 1) # len(last_str) + len(",")
             if count_on_line > 0:
@@ -138,7 +138,7 @@ def __format_wrapped(sequence, open, close, nl):
         last_str = str
         last_lines = item_lines
 
-    if last_str != None:
+    if last_str is not None:
         new_available_width = available_width - (len(last_str) + len(close))
 
         if count_on_line > 0:
@@ -172,7 +172,7 @@ def __format_sequence(obj, open, close, nl, object_stack):
 
     seq = (__format(x, nl, object_stack) for x in obj)
     result = __format_wrapped(seq, open, close, nl)
-    if result == None:
+    if result is None:
         seq = (__format(x, nl, object_stack) for x in obj)
         result = __format_separate(seq, open, close, nl)
 

lib/reinteract/doc_format.py

@@ -37,7 +37,7 @@ def insert_docs(buf, iter, obj, bold_tag):
     pos = 0
     while True:
         m = BOLD_RE.search(document, pos)
-        if m == None:
+        if m is None:
             # Strip the trailing newline; this isn't very justifiable in general terms,
             # but matches what we need in Reinteract
             if document.endswith("\n"):

lib/reinteract/doc_popup.py

@@ -113,7 +113,7 @@ def set_target(self, target):
         buf = self.__view.get_buffer()
         buf.delete(buf.get_start_iter(), buf.get_end_iter())
 
-        if target != None:
+        if target is not None:
             if data_format.is_data_object(target):
                 data_format.insert_formatted(buf, buf.get_start_iter(), target, self.__heading_type_tag, self.__inline_type_tag, self.__value_tag)
             else:

lib/reinteract/editor.py

@@ -31,7 +31,7 @@ def __init__(self, notebook):
     #######################################################
 
     def _clear_unsaved(self):
-        if self._unsaved_index != None:
+        if self._unsaved_index is not None:
             application.free_unsaved_index(self._unsaved_index)
             self._unsaved_index = None
 
@@ -53,7 +53,7 @@ def __prompt_for_name(self, title, save_button_text, action, check_name=None):
         builder = SaveFileBuilder(title, self._get_display_name(), save_button_text, check_name)
         builder.dialog.set_transient_for(self.widget.get_toplevel())
 
-        if self._get_filename() != None:
+        if self._get_filename() is not None:
             builder.name_entry.set_text(os.path.basename(self._get_filename()))
 
         builder.prompt_for_name(self.notebook.folder, self._get_extension(), action)
@@ -90,7 +90,7 @@ def _save(self, filename):
     #######################################################
 
     def close(self):
-        if self._unsaved_index != None:
+        if self._unsaved_index is not None:
             application.free_unsaved_index(self._unsaved_index)
             self._unsaved_index = None
 
@@ -107,7 +107,7 @@ def confirm_discard(self, before_quit=False):
             message_format = self.DISCARD_FORMAT
             continue_button_text = '_Discard'
 
-        if self._get_filename() == None:
+        if self._get_filename() is None:
             save_button_text = gtk.STOCK_SAVE_AS
         else:
             save_button_text = gtk.STOCK_SAVE
@@ -141,10 +141,10 @@ def load(self, filename):
         raise NotImplementedError()
 
     def save(self, filename=None):
-        if filename == None:
+        if filename is None:
             filename = self._get_filename()
 
-        if filename == None:
+        if filename is None:
             def action(fullname):
                 self._save(fullname)
                 self._clear_unsaved()
@@ -155,7 +155,7 @@ def action(fullname):
             self._save(filename)
 
     def rename(self):
-        if self._get_filename() == None:
+        if self._get_filename() is None:
             self.save()
             return
 

lib/reinteract/editor_window.py

@@ -96,7 +96,7 @@ def __save_as(self):
         if response == gtk.RESPONSE_OK:
             filename = chooser.get_filename()
 
-        if filename != None:
+        if filename is not None:
             self.current_editor.save(filename)
             self.path = filename
             self.notebook.set_path([os.path.dirname(filename)])
@@ -111,7 +111,7 @@ def __update_title(self, *args):
     #######################################################
 
     def on_save(self, action):
-        if self.current_editor.filename == None:
+        if self.current_editor.filename is None:
             self.__save_as()
         else:
             self.current_editor.save()

lib/reinteract/file_list.py

@@ -126,9 +126,9 @@ def _next_row_depthfirst(model, iter):
     if model.iter_has_child(iter):
         return model.iter_children(iter)
 
-    while iter != None:
+    while iter is not None:
         next = model.iter_next(iter)
-        if next != None:
+        if next is not None:
             return next
 
         iter = model.iter_parent(iter)
@@ -143,9 +143,9 @@ def _remove_row_depthfirst(model, iter):
     if model.remove(iter):
         return iter
 
-    while parent != None:
+    while parent is not None:
         next = model.iter_next(parent)
-        if next != None:
+        if next is not None:
             return next
 
         parent = model.iter_parent(parent)
@@ -215,7 +215,7 @@ def do_button_press_event(self, event):
             event.button == 3 or (event.button == 1 and event.state == gtk.gdk.CONTROL_MASK)):
 
             info = self.get_path_at_pos(int(event.x), int(event.y))
-            if info == None:
+            if info is None:
                 return False
 
             path, column, cell_x, cell_y = info
@@ -428,7 +428,7 @@ def __rescan(self):
         for (item, new_depth) in self.__iter_items():
             # Delete old items that are logically before the next item
             found_item = False
-            while next_old != None:
+            while next_old is not None:
                 old_item = self.__model.get_value(next_old, 0)
                 c = cmp(item, old_item)
                 if c < 0:
@@ -472,7 +472,7 @@ def __rescan(self):
                 parent = iter
                 depth += 1
 
-        while next_old != None:
+        while next_old is not None:
             next_old = _remove_row_depthfirst(self.__model, next_old)
 
         self.set_show_expanders(seen_folders)
@@ -491,7 +491,7 @@ def select_file(self, file):
         """
 
         iter = self.__iter_for_file(file)
-        if iter == None:
+        if iter is None:
             return
 
         self.set_cursor(self.__model.get_path(iter), self.get_column(0))

lib/reinteract/library_editor.py

@@ -59,7 +59,7 @@ def __update_font(self, *arg):
     #######################################################
 
     def _get_display_name(self):
-        if self.buf.worksheet.filename == None:
+        if self.buf.worksheet.filename is None:
             return "Unsaved Library %d" % self._unsaved_index
         else:
             return os.path.basename(self.buf.worksheet.filename)

lib/reinteract/mini_window.py

@@ -154,7 +154,7 @@ def __update_pages(self):
 
         open_editors = {}
         for editor in self.editors:
-            if editor.file == None:
+            if editor.file is None:
                 items.append(self.__create_editor_item(editor))
             else:
                 open_editors[editor.file.path] = editor

lib/reinteract/new_notebook.py

@@ -58,7 +58,7 @@ def run(parent=None):
             error_message = "<big><b>Please choose a different name</b></big>"
             error_detail = e.message
 
-        if error_message == None:
+        if error_message is None:
             if builder.other_folder_radio_button.get_active():
                 parent_folder = builder.other_folder_chooser.get_filename()
             else:
@@ -69,7 +69,7 @@ def run(parent=None):
                 error_message = "<big><b>Please choose a different name</b></big>"
                 error_detail = "'%s' already exists" % name
 
-        if error_message == None:
+        if error_message is None:
             try:
                 builder.dialog.hide()
                 description = builder.description_text_view.get_buffer().props.text.strip()