Tkinter __call__

[James Stroud]

Gigs_ wrote:
> from Tkinter import *
> from tkFileDialog   import askopenfilename
> from tkColorChooser import askcolor
> from tkMessageBox   import askquestion, showerror
> from tkSimpleDialog import askfloat
> 
> demos = {
>     'Open':  askopenfilename,
>     'Color': askcolor,
>     'Query': lambda: askquestion('Warning', 'You typed          
> "..."\nConfirm?'),
>     'Error': lambda: showerror('Error!', "He's dead, Jim"),
>     'Input': lambda: askfloat('Entry', 'Enter credit card number')
> }
> 
> 
> class Demo(Frame):
>     def __init__(self, parent=None):
>         Frame.__init__(self, parent)
>         self.pack()
>         Label(self, text="Basic demos").pack()
>         for (key, value) in demos.items():
>             func = (lambda key=key: self.printit(key))
>             Button(self, text=key, command=func).pack(side=TOP, fill=BOTH)
>     def printit(self, name):
>         print name, 'returns =>', demos[name]()
> 
> 
> I have tried but cant get it to work properly.
> I want to instead printit method to put __call__ and call it like that
> Can someone help me, please?

The code you have should work. My guess is that you don't understand 
lambda and so you want to do it a "different" way, using a "callable"? 
Well, that's what lambda does, it makes a callable object:


Python 2.5 (r25:51918, Sep 19 2006, 08:49:13)
[GCC 4.0.1 (Apple Computer, Inc. build 5341)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
py> key = 1
py> callable(lambda key=key: self.printit(key))
True
py> '__call__' in dir(lambda key=key: self.printit(key))
True



So the code you have already does what you want to do. Maybe understand 
what you are studying before you reinvent the wheel--you will save 
yourself a lot of frustration.

James