"""Clear Window ExtensionVersion: 0.2Author: Roger D. Serwy        roger.serwy@gmail.comDate: 2009-06-14It provides "Clear Shell Window" under "Options"with ability to undo.Add these lines to config-extensions.def[ClearWindow]enable=1enable_editor=0enable_shell=1[ClearWindow_cfgBindings]clear-window=<Control-Key-l>"""class ClearWindow:    menudefs = [        (‘options‘, [None,               (‘Clear Shell Window‘, ‘<<clear-window>>‘),       ]),]		     def __init__(self, editwin):        self.editwin = editwin        self.text = self.editwin.text        self.text.bind("<<clear-window>>", self.clear_window2)        self.text.bind("<<undo>>", self.undo_event)  # add="+" doesn‘t work    def undo_event(self, event):        text = self.text                text.mark_set("iomark2", "iomark")        text.mark_set("insert2", "insert")        self.editwin.undo.undo_event(event)        # fix iomark and insert        text.mark_set("iomark", "iomark2")        text.mark_set("insert", "insert2")        text.mark_unset("iomark2")        text.mark_unset("insert2")            def clear_window2(self, event): # Alternative method        # work around the ModifiedUndoDelegator        text = self.text        text.undo_block_start()        text.mark_set("iomark2", "iomark")        text.mark_set("iomark", 1.0)        text.delete(1.0, "iomark2 linestart")        text.mark_set("iomark", "iomark2")        text.mark_unset("iomark2")        text.undo_block_stop()        if self.text.compare(‘insert‘, ‘<‘, ‘iomark‘):            self.text.mark_set(‘insert‘, ‘end-1c‘)        self.editwin.set_line_and_column()    def clear_window(self, event):        # remove undo delegator        undo = self.editwin.undo        self.editwin.per.removefilter(undo)        # clear the window, but preserve current command        self.text.delete(1.0, "iomark linestart")        if self.text.compare(‘insert‘, ‘<‘, ‘iomark‘):            self.text.mark_set(‘insert‘, ‘end-1c‘)        self.editwin.set_line_and_column()         # restore undo delegator        self.editwin.per.insertfilter(undo) 

################################# >>> Added for clear Window[ClearWindow]enable=1enable_editor=0enable_shell=1[ClearWindow_cfgBindings]clear-window=<Control-Key-l>