# Use docstrings.
# http://docs.python.org/tutorial/controlflow.html#intermezzo-coding-style
# http://www.python.org/dev/peps/pep-0257/

##random needed for mix method.  Needs to be external to the class
import random

class Bowl:
    ##with a little help from: http://stackoverflow.com/questions/227459/ascii-value-of-a-character-in-python
    ##as well as: http://www.rafekettler.com/magicmethods.html


    def __init__(self, values = []):
        """Constructor"""
        #sorry to change your code, Sean but this allows Bowl to be treated as a list
        #-Actually, this is what I had in mind,
        #   although I don't see where we'd need to have the copy constructor ('values = []')
        #   but it can't hurt
        self.values = values

    def __len__(self):
        """returns length of Bowl"""
        return len (self.values)

    def delitem(self, key):
        """deletes the item at key in self"""
        del self.values[key]

    def top(self):
        """returns the last element in self.values. (top of the stack)"""
        return self.values[-1]

    def put(self, ingredient):
        """appends value to self"""
        self.values.append(ingredient)

    def fold(self, ingredient):
        """sets value of the top of the stack to ingredient"""
        self.values[-1] = ingredient


    def add(self, ingredient):
        """    ##This adds the value of ingredient to the value of the ingredient
    ##on top of the bowl and sets that sum as the new top of the stack,
    ##erasing what was there.
        """
        holder = self.top()
        holder = holder + ingredient
        self.values[-1] = holder


    def remove(self, ingredient):
        """##This subtracts the value of ingredient from the value of the ingredient
    ##on top of the bowl and sets that difference as the new top of the stack,
    ##erasing what was there.
        """
        holder = self.top()
        holder = holder - ingredient
        self.values[-1] = holder

    def combine(self, ingredient):
        """This multiplies the value of ingredient from the value of the ingredient
on top of the bowl and sets that product as the new top of the stack, erasing what was there.
        """
        holder = self.top()
        holder = holder * ingredient
        self.values[-1] = holder


    def divide(self, ingredient):
        """This divides the value of ingredient from the value of the ingredient
        on top of the bowl and sets that quotient as the new top of the stack, erasing what was there.
        """
        holder = self.top()
        holder = holder / ingredient
        self.values[-1] = holder

    def mix(self):
        """This randomises the order of the ingredients"""
        pretend = []
        while(len(self.values)>len(pretend)):
            holder = random.choice(self.values)
            if (pretend.count(holder)>0):
                pass
            else:
                pretend.append(holder)
        self.values = pretend

    def liquify(self):
        """This turns all the ingredients in the bowl into a liquid, i.e. a Unicode characters for output purposes."""
        better = []
        for x in range (len(self.values)):
            better.append(chr(self.values[x]))
        self.values = better

    def __str__(self):
        """to string method, so one can print Bowl when needed """
        return str(self.values)