如何创建一个持续接受用户输入并评估所有输入的程序

How to create a program that continually accepts input from the user and evaluate all the input

如何创建一个不断接受用户输入的程序。

num = 0

while((a := input()) != "-0"):
    if (len(a) >= 2) and (a[0] in "/*-+"):
        num = eval(f"{num}{a}")
    else:
        print("Invalid input, try again.")
        
print(num)