Notepad.py

from tkinter import *
from tkinter.messagebox import showinfo
from tkinter import filedialog
import os

fullpath = ""

def setWinTitle():
    filepath, filename = os.path.split(fullpath)
    docname, ext = os.path.splitext(filename)
    if docname == "":
        titleText = "NOTEPAD - Untitled"
    else:
        titleText = "NOTEPAD - " + docname
    root.title(titleText)

def donothing():
    pass

def newfile():
    global fullpath
    fullpath = ""
    setWinTitle()
    text.delete("1.0", END)

def openfile():
    global fullpath
    filepath, filename = os.path.split(fullpath)
    fullpath = filedialog.askopenfilename(initialdir = filepath, title = "Open", filetypes = (("text files", "*.txt"), ("all files", "*.*")))
    if fullpath == "":
        return
    filepath, filename = os.path.split(fullpath)
    docname, ext = os.path.splitext(filename)
    setWinTitle()
    file = open(fullpath, "r")
    text.delete("1.0", END)
    text.insert(INSERT, file.read())
    file.close()
    
def savefile():
    global fullpath, docname
    filepath, filename = os.path.split(fullpath)
    if filename == "":
        fullpath = filedialog.asksaveasfilename(initialdir = filepath, title = "Save", filetypes = (("text files", "*.txt"), ("all files", "*.*")))
        if fullpath == "":
            return
        filepath, filename = os.path.split(fullpath)
    docname, ext = os.path.splitext(filename)
    setWinTitle()
    if ext.lower() != ".txt":
        fullpath = fullpath + ".txt"
    file = open(fullpath, "w")
    file.write(text.get("1.0", END))
    file.close()     

def saveasfile():
    global fullpath
    filepath, filename = os.path.split(fullpath)
    fullpath = filedialog.asksaveasfilename(initialdir = filepath, title = "Save As", filetypes = (("text files", "*.txt"), ("all files", "*.*")))
    if filename == "":
        return
    filepath, filename = os.path.split(fullpath)
    docname, ext = os.path.splitext(filename)
    setWinTitle()
    if ext.lower() != ".txt":
        fullpath = fullpath + ".txt"
    file = open(fullpath, "w")
    file.write(text.get("1.0", END))
    file.close()

def showhelp():
    showinfo("Notepad Help","You can use File/Open, File/Save, File/Save As, File/Exit, Help/Help Index, Help/About")

def showabout():
    showinfo("About","This is a simple Notepad\nMade using TkInter\nBundled with Python distribution")

def makeMenu():
    menubar = Menu(root)
    filemenu = Menu(menubar)
    menubar.add_cascade(label = "File", menu = filemenu)
    filemenu.add_command(label = "New", command = newfile)
    filemenu.add_command(label = "Open", command = openfile)
    filemenu.add_command(label = "Save", command = savefile)
    filemenu.add_command(label = "Save As", command = saveasfile)
    filemenu.add_separator()
    filemenu.add_command(label = "Exit", command = root.destroy)

    editmenu = Menu(menubar)
    menubar.add_cascade(label = "Edit", menu = editmenu)
    editmenu.add_command(label = "Undo", command = donothing)
    editmenu.add_separator()
    editmenu.add_command(label = "Cut", command = donothing)
    editmenu.add_command(label = "Copy", command = donothing)
    editmenu.add_command(label = "Paste", command = donothing)
    editmenu.add_command(label = "Delete", command = donothing)
    editmenu.add_command(label = "Select All", command = donothing)

    helpmenu = Menu(menubar)
    menubar.add_cascade(label = "Help", menu = helpmenu)
    helpmenu.add_command(label = "Help Index", command = showhelp)
    helpmenu.add_command(label = "About...", command = showabout)
    root.config(menu = menubar)

root = Tk()
setWinTitle()
makeMenu()
scrollbar = Scrollbar(root)
scrollbar.pack(side = RIGHT, fill = Y)
text = Text(root)
text.pack()
scrollbar.config(command = text.yview)
root.mainloop()