Possible constant assignment operators ":=" and "::=" for Python

[Edward Elliott]

Piet van Oostrum wrote:

>>>>>> tsaar2003 at yahoo.com (T) wrote:
> 
>>T> As you can see, the "constant" A can be modified this easily. But if
>>T> there were an intuitive mechanism to declare a symbol to be immutable,
>>T> then there won't be this problem.
> 
> Mutability is not a property of symbols but of values. So it doesn't make
> sense to declare an identifier to be immutable. And mutability is tied to
> the object's type, not to individual instances.

I think he meant immutable binding, not immutable symbol.  So
rebinding/overshadowing a "constant" A would raise an error, but mutating
the underlying object A refers to would not (unless it too were immutable). 
As far objects themselves, adding an ability to make any object immutable
regardless of type is exactly what he suggests.

-- 
Edward Elliott
UC Berkeley School of Law (Boalt Hall)
complangpython at eddeye dot net