Global variables within classes.

[uestc_mahui at 163.com]

On 11 10 ,   5 48 , Donn Ingle <donn.in... at gmail.com> wrote:

> ## == API in another module perhaps ===
> Class Stack:
>  def push(self,stuff):
>   pass
>
> Class Canvas:
>  def do(self):
>   s.push("data") #I don't feel right about 's' here.
>
> Class Thing:
>  def buzz(self):
>   print s.pop(0)
>
> ## == User space code area ===
> s = Stack() #I want to avoid this direct naming to 's'
> c = Canvas()
> c.push("bozo")
> t = Thing()
> t.buzz()
>
> Hope that makes more sense.
> \d


If you mean that all instances of Class Canvas and Thing will share
the *same* Stack, I think we can do it kind of like this:
## == API in another module perhaps ===
class Stack:
    list = []
    def push(self, item):
        self.list.append(item)
    def pop(self):
        item = self.list[-1]
        del self.list[-1]
        return item

class Canvas:
    def __init__(self):
        self.s = Stack()
    def push(self, item):
        self.s.push(item)

class Thing:
    def __init__(self):
        self.s = Stack()
    def buzz(self):
        print self.s.pop()

## == User space code area ===
c = Canvas()
c.push("bozo")
t = Thing()
t.buzz()

or: if you want a pair of instances of class Canvas and class Thing
share
the *same* instance of class Stack, maybe we can make it like this:
## == API in another module perhaps ===
class Stack:
    def __init__(self):
        self.list = []
    def push(self, item):
        self.list.append(item)
    def pop(self):
        item = self.list[-1]
        del self.list[-1]
        return item

class Canvas:
    def __init__(self, stack = Stack()):
        self.s = stack
    def push(self, item):
        self.s.push(item)
    def getStack(self):
        return self.s

class Thing:
    def __init__(self, stack = Stack()):
        self.s = stack
    def buzz(self):
        print self.s.pop()
    def getStack(self):
        return self.s
## == User space code area ===
c = Canvas()
c.push("bozo")
t = Thing(c.getStack())   #associate t with c
t.buzz()