import math
from Custom import CustomBase
import API

class ln (CustomBase):
    stack = None
    
    def __init__(self, stack):
        self.stack = stack
    # __init__
    
    def help(self):
        msg =  "ln\n"
        msg += "--\n\n"
        msg += "Takes r0 from the stack\n\n"
        msg += "Calculates the natural logarithn of r0\n\n"
        msg += "Pushes the result to r0"
        API.showPopup('Custom function', msg, font=('Courier',API.helpFontSize))
    # help

    def calculate(self):
        if self.stack.inputMode != 'DEC':
            API.toast('This operation is only supported in DEC mode')
            return
        if self.stack.finishEntry() == -1: 
            return # abort here because data in input line is invalid
        if self.stack.size() < 1:
            API.beep()
            API.toast('This operation needs 1 argument')
            return
        x = self.stack.getRegister(0)
        self.stack.pop(1)
        self.stack.push(math.log(x))
    # calculate
    
# log