Re: Metaclass conflict TypeError exception: problem demonstration script
Barak, Ron ron.ba...@lsi.com writes: However, when line 7 is in effect (with line 8 commented out), viz.: $ cat -n metaclass_test01.py | head 1 #!/usr/bin/env python 2 3 import sys 4 import wx 5 import CopyAndPaste 6 7 class ListControl(wx.Frame, CopyAndPaste): If this is the actual source you're running, then CopyAndPaste is a module, not a type, and that causes the conflict. Use CopyAndPaste.CopyAndPaste, or change the import line to read from CopyAndPaste import CopyAndPaste. Or, even better, adhere to recommendations laid down in PEP 8 and you'll avoid confusion between module and class names. -- http://mail.python.org/mailman/listinfo/python-list
Metaclass conflict TypeError exception: problem demonstration script
Hi Guys,
Thanks to Michele, Chris, Hrvoje et. al. who helped me trying to resolve the
metaclass exception when a class has two parents problem.
This post tries to unify all the metaclasses exception threads, in an attempt
to reach a solution.
I've created a short demo script (metaclass_test01.py) that demonstrate the
problem.
Listings of metaclass_test01.py and CopyAndPaste are below and attached.
Note:
When line 8 in metaclass_test01.py is in effect (with line 7 commented out),
the script runs normally.
However, when line 7 is in effect (with line 8 commented out), viz.:
$ cat -n metaclass_test01.py | head
1 #!/usr/bin/env python
2
3 import sys
4 import wx
5 import CopyAndPaste
6
7 class ListControl(wx.Frame, CopyAndPaste):
8 #class ListControl(wx.Frame):
9 def __init__(self, parent, id, title, list, max_list_width):
10 wx.Frame.__init__(self,parent,id,title,size=(-1,-1),
style=wx.DEFAULT_FRAME_STYLE)
I get the metaclass conflict exception:
$ python metaclass_test01.py
Traceback (most recent call last):
File metaclass_test01.py, line 7, in module
class ListControl(wx.Frame, CopyAndPaste):
TypeError: Error when calling the metaclass bases
metaclass conflict: the metaclass of a derived class must be a (non-strict)
subclass of the metaclasses of all its bases
I hope that now the problem is demonstrated more clearly, and the gurus out
there could point me in the right direction towards a solution.
Bye,
Ron.
$ cat -n metaclass_test01.py
1 #!/usr/bin/env python
2
3 import sys
4 import wx
5 import CopyAndPaste
6
7 #class ListControl(wx.Frame, CopyAndPaste):
8 class ListControl(wx.Frame):
9 def __init__(self, parent, id, title, list, max_list_width):
10 wx.Frame.__init__(self,parent,id,title,size=(-1,-1),
style=wx.DEFAULT_FRAME_STYLE)
11 self.list = list
12 self.list_ctrl = wx.ListCtrl(self, -1, style=wx.LC_REPORT|
wx.LC_NO_HEADER)
13 self.list_ctrl.InsertColumn(0, title)
14 for i,line_ in enumerate(list):
15 self.list_ctrl.InsertStringItem(i, line_)
16 self.list_ctrl.SetColumnWidth(0, max_list_width)
17
18 self.Bind(wx.EVT_LIST_ITEM_SELECTED, self.OnItemSelected,
self.list_ctrl)
19
20 self.Raise()
21 self.Show(True)
22
23 def OnItemSelected(self, evt):
24 item = evt.GetText()
25 max_list_width = 10 * len(item)
26 ListControl(self, -1, item, item, max_list_width)
27
28 if __name__ == __main__:
29 list = [ First Line, Second Line, Third Line]
30 app = wx.App(redirect=False)
31 max_list_width = 6 * max([len(x) for x in list])
32 ListControl(None, -1, Parent Window, list, max_list_width)
33 app.MainLoop()
$ cat -n CopyAndPaste.py
1 #!/usr/bin/env python
2
3 import wx
4
5 class CopyAndPaste(object):
6
7 def __init__(self):
8 pass
9
10 def set_copy_and_paste(self):
11
12 Setting clipboard copy-and-pasting (only copying from the
application to the
13 clipboard is supported).
14 The menu menu is hidden, and is only there to facilitate the
acceleration table.
15 Both CTRL-C and CTRL-Ins are supported.
16
17 menu = wx.Menu()
18 copy_ = menu.Append(-1, Copy\tCtrl-Ins) # Copy with
accelerator
19 minimize_ = menu.Append(-1, Minimize) #
20 close_ = menu.Append(-1, Close window\tCtrl-W) # Close window
21 exit_ = menu.Append(-1, Exit application\tCtrl-X) # Close
window
22
23 self.Bind(wx.EVT_MENU, self.on_copy, copy_)
24 self.Bind(wx.EVT_MENU, self.on_minimize, minimize_)
25 self.Bind(wx.EVT_MENU, self.on_close, close_)
26 self.Bind(wx.EVT_MENU, self.on_exit, exit_)
27
28 menuBar = wx.MenuBar()
29 self.SetMenuBar(menuBar)
30
31 acceltbl = wx.AcceleratorTable( [
32 (wx.ACCEL_CTRL, ord('C'), copy_.GetId()),
33 (wx.ACCEL_CTRL, ord('W'), close_.GetId()),
34 (wx.ACCEL_CTRL, ord('X'), exit_.GetId()),
35 (wx.ACCEL_CTRL, ord('Q'), exit_.GetId()),
36 (wx.ACCEL_CTRL, wx.WXK_INSERT, copy_.GetId()),
37 (wx.ACCEL_CTRL, wx.WXK_NUMPAD_INSERT, copy_.GetId()),
38 ])
39 self.SetAcceleratorTable(acceltbl)
40
41 # Setting popup menu
42
43 self.popupmenu = menu
44 self.Bind(wx.EVT_CONTEXT_MENU, self.on_show_popup)
45
46 def on_show_popup(self, evt):
47
Re: Metaclass conflict TypeError exception: problem demonstration script
$ cat -n metaclass_test01.py | head 1 #!/usr/bin/env python 2 3 import sys 4 import wx 5 import CopyAndPaste 6 7 class ListControl(wx.Frame, CopyAndPaste): 8 #class ListControl(wx.Frame): 9 def __init__(self, parent, id, title, list, max_list_width): 10 wx.Frame.__init__(self,parent,id,title,size=(-1,-1), style=wx.DEFAULT_FRAME_STYLE) I get the metaclass conflict exception: You're trying to use a module as a base class. Don't do that; it doesn't work. TJG -- http://mail.python.org/mailman/listinfo/python-list
Re: Metaclass conflict TypeError exception: problem demonstration script
En Mon, 23 Feb 2009 07:32:52 -0200, Barak, Ron ron.ba...@lsi.com escribió: $ cat -n metaclass_test01.py | head 1 #!/usr/bin/env python 2 3 import sys 4 import wx 5 import CopyAndPaste 6 7 class ListControl(wx.Frame, CopyAndPaste): 8 #class ListControl(wx.Frame): 9 def __init__(self, parent, id, title, list, max_list_width): 10 wx.Frame.__init__(self,parent,id,title,size=(-1,-1), style=wx.DEFAULT_FRAME_STYLE) I get the metaclass conflict exception: $ python metaclass_test01.py Traceback (most recent call last): File metaclass_test01.py, line 7, in module class ListControl(wx.Frame, CopyAndPaste): TypeError: Error when calling the metaclass bases metaclass conflict: the metaclass of a derived class must be a (non-strict) subclass of the metaclasses of all its bases I hope that now the problem is demonstrated more clearly, and the gurus out there could point me in the right direction towards a solution. You want the CopyAndPaste *class*, not the *module*! -- Gabriel Genellina -- http://mail.python.org/mailman/listinfo/python-list
Solved: Metaclass conflict TypeError exception: problem demonstration script
Hi, -Original Message- From: Tim Golden [mailto:m...@timgolden.me.uk] Sent: Monday, February 23, 2009 11:37 Cc: python-list@python.org; wxpython-us...@lists.wxwidgets.org Subject: Re: Metaclass conflict TypeError exception: problem demonstration script $ cat -n metaclass_test01.py | head 1 #!/usr/bin/env python 2 3 import sys 4 import wx 5 import CopyAndPaste 6 7 class ListControl(wx.Frame, CopyAndPaste): 8 #class ListControl(wx.Frame): 9 def __init__(self, parent, id, title, list, max_list_width): 10 wx.Frame.__init__(self,parent,id,title,size=(-1,-1), style=wx.DEFAULT_FRAME_STYLE) I get the metaclass conflict exception: You're trying to use a module as a base class. Don't do that; it doesn't work. TJG That's it. Once I changed my class header to: $ cat -n metaclass_test01.py 1 #!/usr/bin/env python 2 3 import sys 4 import wx 5 import CopyAndPaste 6 7 class ListControl(wx.Frame, CopyAndPaste.CopyAndPaste): I'm getting no more Metaclass conflict TypeError exceptions :-) (a clear case of The Devil Is In The ...) Thanks so much, Ron. -- http://mail.python.org/mailman/listinfo/python-list
Re: Solved: Metaclass conflict TypeError exception: problem demonstration script
Barak, Ron wrote: That's it. Once I changed my class header to: $ cat -n metaclass_test01.py 1 #!/usr/bin/env python 2 3 import sys 4 import wx 5 import CopyAndPaste 6 7 class ListControl(wx.Frame, CopyAndPaste.CopyAndPaste): I'm getting no more Metaclass conflict TypeError exceptions :-) (a clear case of The Devil Is In The ...) Glad we could help. Also a good indication of how important it is to produce real code which really fails in the real way! Sometimes you can look at it yourself even before you post and see the problem. :) TJG -- http://mail.python.org/mailman/listinfo/python-list
