from tkinter import *
import string
import ctypes

xAxis = string.ascii_lowercase[0:7]
yAxis = range(0, 12)

cells = {}


def evaluateCell(cellId):
    content = cells[cellId][0].get()
    content = content.lower()

    label = cells[cellId][1]

    if content.startswith('='):
        for cell in cells:
            if cell in content.lower():
                content = content.replace(cell, str(evaluateCell(cell)))

        content = content[1:]
        try:
            content = eval(content)
        except:
            content = 'NAN'
        label['text'] = content
        return content

    else:
        label['text'] = content
        return content


def updateAllCells():
    root.after(10, updateAllCells)

    for cell in cells:
        evaluateCell(cell)


root = Tk()
root.resizable(0, 0)
root.title('Приложение для электронных таблиц')

for y in yAxis:
    label = Label(root, text=y, width=5, background='white')
    label.grid(row=y + 1, column=0)

for i, x in enumerate(xAxis):
    label = Label(root, text=x, width=35, background='white')
    label.grid(row=0, column=i + 1, sticky='n')

for y in yAxis:
    for xcoor, x in enumerate(xAxis):
        id = f'{x}{y}'

        var = StringVar(root, '', id)

        e = Entry(root, textvariable=var, width=30)
        e.grid(row=y + 1, column=xcoor + 1)

        label = Label(root, text='', width=5)
        label.grid(row=y + 1, column=xcoor + 1, sticky='e')

        cells[id] = [var, label]

updateAllCells()

root.mainloop()