expression evaluator

# input -> "sub(1,3)" output -> -2
# operations take only 2 params. commands may be nested.
# ie. add(sub(3,4), 1), sub(add(238943, 2343), add(1, sub(323, 43)))
import numpy as np


operators = ['add', 'sub', 'mul', 'div']
input_ = "add(3,4)"
#input_ = "add(sub(3,4),1)"



# operator wont be a leaf. operands will be
map = {'add':'a',
       'sub': 's',
       'mul': 'm',
       'div': 'd'}

operator_map = {'a' : np.add,
                's' : np.subtract,
                'm' : np.multiply,
                'd' : np.divide}


for word, initial in map.items():
    input_ = input_.replace(word.lower(), initial)

tokens = list(input_)

def remove_items(test_list, item):
    res = [i for i in test_list if i != item]
    return res

tokens = remove_items(tokens, "(")
tokens = remove_items(tokens, ")")
tokens = remove_items(tokens, ",")

print(tokens)



def evaluate(tmp):

    for index, element in enumerate(tmp):
        if element in ['a', 's', 'm', 'd']:
            operator = operator_map[element]
            operand_l = tmp[2*index+1]
            operand_r = tmp[2*index+2]

            if operand_l.isdigit() and operand_r.isdigit():
                return operator(int(operand_l), int(operand_r))
            # elif operand_l isdigit():
            #     evaluate()
            #     return operator(operand_l, )




print(evaluate(tokens))