def generate_table(self, show_message):
# convert the entered string into a standard format
expression = self.entry.get()
print("Expression: {}".format(expression))
# validate that the expression is consistant with the rules
try:
expression = EP.format_expression(expression)
EP.validate(expression)
# generate table
# draw table
except EP.InvalidExpressionException as ex:
if show_message:
messagebox.showinfo('Error', ex)
except Exception as ex:
print('Unexpected exception! Exception message: {}'.format(
ex.message))
