Vicent wrote:
On Sat, Jan 24, 2009 at 19:48, bob gailer <bgai...@gmail.com>
wrote:
The problem is: there is no
way that I know of to add fundamental types
to Python. Also realize that variables are dynamically typed - so any
assignment can create a variable of a new type. That is why a = 0
results in an int.
So one must resort, as others have mentioned, to classes.
Yes, that's what I understood from previous answers.
Framework
(untested):
class Bit:
_value = 0 # default
def __init__(self, value):
self._value = int(bool(value))
def getvalue(self):
return self._x
def setvalue(self, value):
self._x = int(bool(value))
value = property(getvalue, setvalue)
def __add__(self, other): # causes + to act as or
self._value |= other
def __mul__(self, other): # causes * to act as and
self._value &= other
b = Bit(1)
b.value # returns 1
b.value = 0
b.value # returns 0
b.value + 1 # sets value to 1
b.value * 0 # sets value to 0
Wow! that's great. I'll give it a try.
It would be great if "b.value = 0" could be just written as "b = 0"
without changing type as a result.
Assignment in effect does a del b, then creates a new b based on the
_expression_. There is no way in Python right now to do that. The closest
I can come is to support the syntax b(0) and b(1) to emulate
assignment. That would require that I add to the Bit class:
def __call__(self, value):
self.value = value
What happens if every time I want to update the value of "b", I use "b=
Bit(0)" , "b=Bit(1)", and so on?? Is like "building" the object each
time? It is less efficient, isn't it?
Yes and yes.
Are you saying that to prepare your self for a negative response from
me, or in hopes that I would not have such? I view everything we do
here as incremental improvement. I am glad you are thinking of
alternatives.
, but... Maybe the solution is not to re-define what already
exists —boolean data type, but just using it, as suggested at the
beginning of the thread...
b = bool(1)
b = bool(0)
After all, it's not so bad...
It really depends on your goals for having this new type.
--
Bob Gailer
Chapel Hill NC
919-636-4239
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