eval_expr.py

#!/usr/bin/python3
#
# Written for Python 3.7
from __future__ import annotations
from typing import Callable

def and_x(a: bool, b: bool) -> bool:
    return a and b

def or_x(a: bool, b: bool) -> bool:
    return a or b

def not_x(a: bool) -> bool:
    return not a

def xor_x(a: bool, b: bool) -> bool:
    return a ^ b

def nand_x(a: bool, b: bool) -> bool:
    return not and_x(a, b)

def print_truth_table(f: Callable[[bool, bool], bool]) -> None:
    print("_" * 25)
    print("|   A   |   B   |       |")
    print("-" * 25)
    for (left, right) in ((True, True), (True, False), (False, True), (False, False)):
        print(f"|   {'W' if left else 'F':4}|   {'W' if right else 'F':4}|   {'W' if f(left, right) else 'F':4}|")
    print("-" * 25)

def xor(left: bool, right: bool) -> bool:
    return not_x(or_x(and_x(left, right), not_x(or_x(left, right))))

print_truth_table(and_x)
print("\n")
print_truth_table(xor)
print("\n")
print_truth_table(nand_x)