Real World usage of D, Today (was Re: challenge #2: implement the varargs_reduce metafunction)

[Bill Baxter]

Andrei Alexandrescu (See Website For Email) wrote:
> Frits van Bommel wrote:
>> Andrei Alexandrescu (See Website For Email) wrote:
>>> The syntax that I am proposing does away with storageof and is very 
>>> much in spirit with the current D:
>>>
>>> S int foo(S, T)(S T t) { }
>>>
>>> It does exactly what it says it does, in a clear and terse manner, 
>>> and is 100% within the spirit of existing D:
>>>
>>> * It's customized on symbols S and T
>>>
>>> * It's matching (by sheer position of S and T) the storage (i.e., all 
>>> of the gooey fuzzy nice information about the argument passed) and 
>>> the type of the incoming argument
>>>
>>> * In this example it uses the storage in the result type (e.g. const 
>>> goes to const)
>>>
>>> * Inside the function can easily use either T separately or S T as a 
>>> group that transports the storage around. You have total flexibility 
>>> (and don't forget that juxtaposition is always easier than extraction).
>>>
>>> So far we're only thinking of storage-like attributes, but a good 
>>> deal of information can be encoded under the loose declaration of 
>>> "storage".
>>
>> Would it also be possible to 'cherry-pick' attributes?
>> So that e.g something like S.constness expands to either 'const' or ''?
>>
>> And would this mean 'raw' storage attributes would be valid template 
>> parameters? So that something like foo!(const) would be valid syntax?
> 
> You will be able to cherry-pick with "is" tests. Walter is opposed to 
> manipulating the raw storage attributes.

If you have to cherry pick with "is" tests to separate the bits out of 
the S above, then why not just use "is" tests to pick the S info off the 
type to begin with?

--bb