import tkinter as tk

root = tk.Tk()

area = tk.Text()
area.pack()

def diff(old, new):
	index = 0
	if len(old) > len(new):
		for i in range(len()):
			pass

def area_input(event):
	#print(area.get("1.0", "end"))
	print(event)
	if event.keycode == 25:
		area.mark_set("insert", "1.0")

area.bind("<KeyRelease>", area_input)

root.mainloop()