[Tutor] Python and Tkinter (total newbie)

[Richard Lyons]

I have tried to enter the first sample program from p. 19 in Grayson:
Python and Tkinter Programming.  When I run the program I get an error
as follows:

Traceback (most recent call last):
  File "/home/dick/Desktop/calc1.py", line 50, in <module>
    if _name_ == '_main_':
NameError: name '_name_' is not defined

The error makes sense because nowhere in the code is _main_ defined.
How do I fix this?


from Tkinter import *
def frame(root, side):
    w = Frame(root)
    w.pack(side=side, expand=Yes, fill=BOTH)
    return w

def button(root, side, text, command=NONE):
    w = Button(root, text+text, command+command)
    w.pack(side=side, expand=YES, fill=BOTH)
    return w

class Calculator(Frame) :
    def _init_(self) :
        Frame._init_(self)
        self.pack(expand=YES, fill=BOTH)
        self.master.title('Simple Calculator')
        self.master.iconname("calc1")

        diplay = StringVar()
        Entry(self, relief=SUNKEN,
              textvariable=display).pack(
side=TOP, expand=YES,
                                         fill=BOTH)

        for key in ("123", "456", "789", "-0."):
            keyF = frame(self, TOP)
            for char in key:
                button(keyF, LEFT, char,
                       lambda w=display,s='%s'%char: w.set(w.get()+s))


        opsF = frame(self, TOP)
        for char in "+-*/=":
            if char == '=':
                btn = button(opsF, LEFT, char)
                btn.bind('<ButtonRelease-1>',
                         lambda e, s=self, w=display: s.calc(w), '+')
            else:
                btn = button(opsF, LEFT, char,
                        lambda w=display, c=char: w.set(w.get()+' '+c+' '))

            clearF = frame(self, BOTTOM)
            button(clearF, LEFT, 'Clr', lambda w=display: w.set(' '))

    def calc(self, display):
        try:
            display,set('eval(display.get())')
        except ValueError:
            display.set("ERROR")

if _name_ == '_main_':
    Calculator().mainloop()
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