python做简易记事本

from tkinter import *
from tkinter.filedialog import *
from tkinter.messagebox import *
import os
filename=''
def author():
    showinfo('大道至简','简易记事本第一版')

def power():
    showinfo('版权信息','本公司保留版权信息，不可以把本软件用于商业目的！')
def myopen():
    global filename
    filename=askopenfilename(defaultextension='.txt')
    if filename=='':
        filename=None
    else:
        root.title('简易记事本'+os.path.basename(filename))
        textPad.delete(1.0,END)
        f=open(filename,'r')
        textPad.insert(1.0,f.read())
        f.close()


def new():
    global root,filename,textPad
    root.title('未命名文件')
    filename=None
    textPad.delete(1.0,END)

def save():
    global filename
    try:
        f=open(filename,'w')
        msg=textPad.get(1.0,'end')
        f.write(msg)
        f.close()
    except:
        saveas()
def saveas():
    f=asksaveasfile(initialfile='未命名.txt',defaultextension='.txt')
    global filename
    filename=f
    fh=open(f,'w')
    msg=textPad.get(1.0,END)
    fh.write(msg)
    fh.close()
    root.title('简易记事本'+os.path.basename(f))
def cut():
    global textPad
    textPad.event_generate('<<Cut>>')
def copy():
    global textPad
    textPad.event_generate('<<Copy>>')
def paste():
    global textPad
    textPad.event_generate('<<Paste>>')


def undo():
    global textPad
    textPad.event_generate('<<Undo>>')
def redo():
    global textPad
    textPad.event_generate('<<Redo>>')
def select_all():
    global textPad
    textPad.tag_add('sel','1.0','end')
def find():
    global root
    t=Toplevel(root)
    t.title('查找')
    t.geometry('260x60+200+250')
    t.transient(root)
    Label(t,text='查找：').grid(row=0,column=0,sticky='e')
    v=StringVar()
    e=Entry(t,width=20,textvariable=v)
    e.grid(row=0,column=1,padx=2,pady=2,sticky='we')
    e.focus_set()
    c=IntVar()
    Checkbutton(t,text='不区分大小写',variabel=c).grid(row=1,column=1,sticky='e')
    Button(t,text='查找所有',command=lambda :search(v.get(),c.get(),textPad,t,e)).grid(row=0,
        column=2,sticky='e'+'w',padx=2,pady=2)
def close_search():
    textPad.tag_remove('match','1.0',END)
    t.destroy()
    t.protocol('WM_DELETE_WINDOW',close_search)#???

def search(needle,cssnstv,textPad,t,e):
    textPad.tag_remove('match','1.0',END)
    count=0
    if needle:
        pos='1.0'
        while True:
            pos=textPad.search(needle,pos,nocase=cssnstv,stopindex=END)
            if not pos:break
            lastpos=pos+str(len(needle))
            textPad.tag_add('match',pos,lastpos)
            count+=1
            pos=lastpos
        textPad.tag_config('match',foreground='yellow',background='green')
        e.focus_set()
        t.title(str(count)+'个被匹配')

def popup(event):
    global editmenu
    editmenu.tk_popup(event.x_root,event.y_root)
root=Tk()
root.title('简易记事本第一版')
root.geometry('300x300+100+100')#geometry(wxh+xoffset+yoffset)
menubar=Menu(root)#制作菜单实例，依附于父窗口root上面

filemenu=Menu(menubar)#制作文件菜单项，依附于menubar菜单上面
menubar.add_cascade(label='文件',menu=filemenu)#增加分层菜单
filemenu.add_command(label='新建',accelerator='Ctrl+N',command=new)
filemenu.add_command(label='打开',accelerator='Ctrl+O',command=myopen)
filemenu.add_command(label='保存',accelerator='Ctrl+S',command=save)
filemenu.add_command(label='另存为',accelerator='Ctrl+Alt+S',command=saveas)

editmenu=Menu(menubar)#制作编辑菜单项，依附于menubar菜单上面
menubar.add_cascade(label='编辑',menu=editmenu)
editmenu.add_command(label='撤销',accelerator='Ctrl+Z',command=undo)
editmenu.add_command(label='重做',accelerator='Ctrl+Y',command=redo)
editmenu.add_command(label='剪切',accelerator='Ctrl+X',command=cut)
editmenu.add_command(label='复制',accelerator='Ctrl+C',command=copy)
editmenu.add_command(label='粘贴',accelerator='Ctrl+V',command=paste)
editmenu.add_separator()
editmenu.add_command(label='查找',accelerator='Ctrl+F',command=find)
editmenu.add_command(label='全选',accelerator='Ctrl+A',command=select_all)

aboutmenu=Menu(menubar)#制作关于菜单项，依附于menubar菜单上面
menubar.add_cascade(label='关于',menu=aboutmenu)#增加分层菜单
aboutmenu.add_command(label='作者',command=author)
aboutmenu.add_command(label='版权',command=power)
root.config(menu=menubar)
shortcutbar=Frame(root,height=25,bg='light sea green')
shortcutbar.pack(expand=NO,fill=X)
Inlabel=Label(root,width=2,bg='antique white')
Inlabel.pack(side=LEFT,anchor='nw',fill=Y)

textPad=Text(root,undo=True)
textPad.pack(expand=YES,fill=BOTH)
scroll=Scrollbar(textPad)
textPad.config(yscrollcommand=scroll.set)
scroll.config(command=textPad.yview)
scroll.pack(side=RIGHT,fill=Y)

textPad.bind('<Control-N>',new)
textPad.bind('<Control-n>',new)
textPad.bind('<Control-O>',myopen)
textPad.bind('<Control-o>',myopen)
textPad.bind('<Control-S>',save)
textPad.bind('<Control-s>',save)
textPad.bind('<Control-A>',select_all)
textPad.bind('<Control-a>',select_all)
textPad.bind('<Control-f>',find)
textPad.bind('<Control-F>',find)
textPad.bind('<Control-3>',popup)

root.mainloop()