const by default.

[Don Clugston]

Sean Kelly wrote:
> BCS wrote:
>> Deewiant wrote:
>>>
>>>
>>> I think there's a problem with all this "grant 
>>> mutability/immutability", which
>>> is that we're just degenerating into C++ with its const_cast. With 
>>> it, the
>>> compiler has few, if any, guarantees about the constness of anything 
>>> --- it can
>>> always be casted away.
>>
>> Casting away mutability (unless I'm totally nuts) is always safe. 
>> Casting away immutability should never be allowed.
> 
> Exactly.  This is much of the reason for the "const as default" idea, as 
> it makes sense to convert something to a more general representation (in 
> this case mutable to immutable) but not vice-versa.  C++ got this 
> backwards by making mutable the general category.

And then had to add the 'mutable' keyword anyway <g>.