D const design rationale

[Derek Parnell]

On Tue, 26 Jun 2007 11:46:30 -0700, Walter Bright wrote:

> Oskar Linde wrote:
>> Walter Bright skrev:
>>> OF wrote:
>>>> Walter Bright Wrote:
>>>>
>>>>> BLS wrote:
>>>>>> I am afraid you will not like this idea, but not afraid enough. <g>
>>>>>>
>>>>>> Why not using a single keyword "const_" adding a number 1, 2, 3 to 
>>>>>> represent :
>>>>>> invariant, final, readonlyview.
>>>>>> the higher the number the higher (the stronger) the const.
>>>>>> means : const_3 == invariant;
>>>>>> At least a mental help, IMO; somehow borrowed from Modula 2 processes.
>>>>> You're right, I don't like the idea <g>.
>>>>
>>>> I'm curious. Was 'readonly'
>>>
>>> readonly is a synonym for const, so no improvement there.
>> 
>> Read-only isn't synonymous with constant.
> 
> Consider ROM, i.e. "Read Only Memory".

Which is obviously misnamed. It should be more like Write-Once memory <G>
If it were truely *always* read-only then nothing would ever be written to
it, thus it is not constant as its state has changed at least once.


-- 
Derek Parnell
Melbourne, Australia
skype: derek.j.parnell