Extended Type Design ~ don't forget about enum

[Andrei Alexandrescu (See Website For Email)]

kris wrote:
> Lars Ivar Igesund wrote:
>> Don Clugston wrote:
>>
>>
>>> I completely agree with this. The gripe I have is that 'const' is a
>>> completely inappropriate term for 'const-as-in-C++'. It's a bizarre
>>> misnomer to use 'const' to mean "don't touch". The only benefit (albeit
>>> a considerable one) of this nomenclature is compatibility with C++
>>> nomenclature, especially the term "const correctness".
>>> D currently has a 'const' which actually means "constant", it seems
>>> dreadful to exchange that for a clearly inferior "don't touch" meaning.
>>> I'm concerned that you may have spent so much time in C++ that you've
>>> become accustomed to "const" == "don't touch"; all of my previous posts
>>> have been arguing that this is a grossly unnatural association.
>>>
>>> It is possible that the C++ misnomer is so entrenched that D needs to
>>> perpetuate it, even at the expense of breaking all existing D code that
>>> uses 'const'.
>>
>>
>> I agree with Don here.
> 
> 
> So do I
> 
> Was somewhat hoping invariant would be used in place of what has now 
> taken shape as "const", and "constant" would be used in place of where 
> "invariant" has landed. Then there would be no "const" to confuse 
> anyone. Almost seems as though shortening the name by a couple of bytes 
> is actually more important than the meaning of the words in use?

I think the 5 letters to 9 letters a difference, especially when 
repeated many times. And again: invariant and const are synonims. 
Merriam-Webster lists "constant" as the first meaning of "invariant":

http://m-w.com/dictionary/invariant

> I'm not sure about "breaking all existing D code" ... there would seem 
> to be very little use of "const" at this time, because the current 
> semantics are really kinda worthless; e.g. one should probably use enum 
> for most things 'constant', except you can't have "enum : char[]" making 
> enum notably less useful than it could otherwise be.
> 
> Where does enum fit in this picture anyway? Can it recover some duty 
> from "const" and/or "final" in a logical and consistent manner?

If I had my way, I'd make the language powerful enough to express 
enumerated types in stdlib, then I'd deprecate the built-in one.


Andrei