A Dozenal Reverse Polish Calculator

reverse.py

# A reverse polish calculator for the dozenal system

def dozToDec(doz):
    dozenal = None
    if '.' in doz:
        doz, dozenal = doz.split('.')
    sum = 0
    for i in range(len(doz)):
        addition = DOZ_DIGITS.index(doz[len(doz) - i - 1])
        for _ in range(i):
            addition *= 12
        sum += addition
    if dozenal:
        for i in range(len(dozenal)):
            addition = DOZ_DIGITS.index(dozenal[i])
            for _ in range(i + 1):
                addition /= 12
            sum += addition
    return sum

def decimalToDoz(decimal):
    doz = ""
    for i in range(DPRCSN):
        doz += DOZ_DIGITS[int(decimal*12)]
        decimal = decimal*12 % 1
        if decimal < 1/(10**(DPRCSN - i)):
            break
    return doz

def decToDoz(dec):
    if type(dec) == complex:
        real = decToDoz(dec.real)
        imag = decToDoz(dec.imag)
        return real + ' ' + imag + " i * +"
    decimal = None
    if dec % 1:
        decimal = dec % 1
    dec = int(dec)
    doz = ""
    while dec > 0:
        doz = DOZ_DIGITS[dec % 12] + doz
        dec //= 12
    if decimal:
        doz += '.' + decimalToDoz(decimal)
    elif doz == "":
        doz = "0"
    return doz

def splitExpr(expr):
    split = []
    num = ""
    for char in expr:
        if char in DOZ_DIGITS or (char == '.' and '.' not in num):
            num += char
        elif char in OPS + COMMANDS:
            if len(num) > 0:
                split.append(num)
                num = ""
            split.append(char)
        elif char == ' ':
            if len(num) > 0:
                split.append(num)
                num = ""
        else:
            print("Error: `{}` is not a valid syntax".format(char))
            return []
    if num:
        split.append(num)
    return split

def processExpr(stack, expr):
    for item in splitExpr(expr):
        if item in COMMANDS:
            if item in "pd":
                if len(stack) == 0:
                    print("Stack is empty")
                elif item == 'p':
                    print(decToDoz(stack[-1]))
                elif item == 'd':
                    print("{} ({})".format(decToDoz(stack[-1]), stack[-1]))
            elif item == 'c':
                stack.clear()
                clearScreen()
            elif item == 'q':
                exit()
        elif item in OPS:
            if len(stack) < 2:
                print("Not enough items in the stack: ignoring `{}`".format(item))
            else:
                second = stack.pop()
                first = stack[-1]
                if item == '+':
                    result = first + second
                elif item == '-':
                    result = first - second
                elif item == '*':
                    result = first*second
                elif item == '/':
                    result = first/second
                elif item == '^':
                    result = first**second
                stack[-1] = result
        else:
            stack.append(dozToDec(item))

def clearScreen():
    print("\x1b[2J\x1b[1;1H")

DPRCSN = 12
DOZ_DIGITS = "0123456789XE"
OPS = "+-*/^"
COMMANDS = "pdcq"

# TODO: implement constants
CONSTS = {
    "$pi": 3.141592653589793,
    "$e": 2.718281828459045
}

if __name__ == "__main__":
    stack = []
    while True:
        expr = input()
        processExpr(stack, expr)