I’m trying to add a Listener to a topic, where the Listener is a curried function (has one parameter), and it seems like it should work - but it doesn’t. 
from functools import partial
def new_game_msg(*args):
pub.sendMessage(topicName='game.new', some_data='this is a test message')
def MakeStatusBar(top_frame):
statusbar = top_frame.CreateStatusBar()
statusbar.SetFieldsCount(3)
statusbar.SetStatusWidths([200, 200, -2])
status_func = partial(got_status_msg, statusbar)
status_func(some_data='Directly testing function currying') # Works
pub.subscribe(listener=status_func, topicName='game.new') # Breaks
# pub.subscribe(listener=got_msg, topicName='game.new') # Works, when alone
return statusbar
def got_status_msg(status_bar, some_data):
print(f"*** got_status_msg, args = {some_data}\n")
status_bar.SetStatusText(some_data, 0)
def got_msg(some_data):
print(f"*** got_msg: data = {some_data}\n")
I’d like the Listener to have a pointer to a StatusBar, for posting messages. (Note this is just experimentation-code, learning WxPython.) The error is:
Traceback (most recent call last):
File "/Code/wxpy/hex_test/src/wx/menu_bar.py", line 11, in new_game_msg
pub.sendMessage(topicName='game.new', some_data='this is a test message')
raise SenderUnknownMsgDataError(self.topicNameTuple,
pubsub.core.topicargspec.SenderUnknownMsgDataError:
Some optional args unknown in call to sendMessage('('game', 'new')', some_data): some_data
The Listener, as I understood it, can be any Callable - so is there a way of making this work? Thanks.
I’m guessing you can’t re-edit posts? Not finding it, if so. Anyway, I updated the code to be a fully working example, partly as an attempt at rubber-ducking. It didn’t work, the problem is still there.
from functools import partial
import time
import wx
from pubsub import pub
def MakeStatusBar(top_frame):
statusbar = top_frame.CreateStatusBar()
statusbar.SetFieldsCount(2)
statusbar.SetStatusWidths([400, 400])
# pub.subscribe(listener=got_msg, topicName='game.new') # Works, when alone
status_func = partial(got_status_msg, statusbar)
print(f"status_func[callable={callable(status_func)}] = {status_func}")
status_func(some_data='Directly calling the curried-function') # Calling the function directly - works
pub.subscribe(listener=status_func, topicName='game.new') # Breaks
return statusbar
def got_msg(some_data):
print(f"\n*** got_msg: data = {some_data}\n")
def got_status_msg(status_bar, some_data):
print(f"\n*** got_status_msg, args = {some_data}\n")
status_bar.SetStatusText(some_data, 0)
class topFrame(wx.Frame):
def __init__(self, parent):
super().__init__(parent, wx.ID_ANY, title='testing', size=(500, 500))
self.status_bar = (MakeStatusBar(self))
class myApp(wx.App):
def __init__(self):
wx.App.__init__(self, redirect=True, filename='errlog.txt') # To log error to a file
# super().__init__(self) # Doesn't take redirect? Weird.
self.topFrame = topFrame(None)
self.SetTopWindow(self.topFrame)
self.topFrame.Show()
print(f"in 2 seconds, will send a message to the Statusbar")
time.sleep(2)
print(f"sending...\n")
try:
pub.sendMessage(topicName='game.new', some_data='publishing a new-game message')
except Exception as ex:
print(f"WTF? got {str(ex)}\n")
print(f"message has been sent.\n")
if __name__ == '__main__':
my_app = myApp()
my_app.MainLoop()
I don’t know if it’s a problem with my code, or understanding of the libraries, but it certainly feels like a bug, or some kind of “magic” going on under-the-hood of PyPubSub, to find the callable, instead of just calling it.
Imagine my surprise, to find out there is a solution, baked into PyPubSub. The listener itself already allows for curried arguments. I can just directly pass in the StatusBar parameter I want.
# status_func = partial(got_status_msg, statusbar)
# print(f"status_func[callable={callable(status_func)}] = {status_func}")
# status_func(some_data='Directly calling the curried-function') # Calling the function directly - works
pub.subscribe(listener=got_status_msg, topicName='game.new', status_bar=statusbar) # Now works
Clearly the developers of PyPubSub, know what they’re doing. Good work.
I thought the current version of PyPubSub did away with *args and now requires named keywords or no arguments.
Yeah, but I just tried the curried-function with a keyword, and it didn’t work either.
status_func = partial(got_status_msg, status_bar=statusbar)
So using the built-in function-currying is the only solution.