from lexer import tokenize


def evaluate(text):
    """Evaluates with * and / binding tighter than + and -."""
    tokens = tokenize(text)
    # First pass: fold the high-precedence operators.
    folded = [tokens[0]]
    index = 1
    while index < len(tokens):
        op, rhs = tokens[index], tokens[index + 1]
        if op == "*":
            folded[-1] = folded[-1] * rhs
        elif op == "/":
            folded[-1] = folded[-1] // rhs
        else:
            folded.append(op)
            folded.append(rhs)
        index += 2
    # Second pass: left-to-right over what is left.
    total = folded[0]
    index = 1
    while index < len(folded):
        op, rhs = folded[index], folded[index + 1]
        total = total + rhs if op == "+" else total - rhs
        index += 2
    return total