On Saturday, 25 January 2014 18:36:59 UTC+1, David Piepgrass wrote:
>
>
> 3. Julia has first class types, so types are values in the language. Tuple
>> types are written as a tuple of the types, which seems fairly
>> straight-forward. Your version, Tuple{Int,Int}, would require a new type
>> for each size of tuple (or would have a different representation than you
>> suggested). I don't understand what you would gain by having a separate
>> type that basically reimplements the same functionality as a tuple. Could
>> you offer a concrete example of a problem this could cause?
>>
>
> The point is that a tuple is sometimes a type-of-type and other times it
> is just an ordinary value. So if there were a superclass of all types of
> types (as is the case in most languages with reflection), some tuples would
> be subclasses of it and others would not be. It's just ... so ... weird.
> I'm not claiming it's problematic, I'm *asking* if it is ever problematic.
>
It is actually a bit problematic, occasionally. The Tuple{Int,Int} variant
has been mentioned at some point in the discussion, a good while back.
It probably doesn't come up very often in practice, but at least for me who
does a lot of metaprogramming, I have sometimes had to work around the fact
that I can't specify the type of a type. I think that this is something
that would be nice to fix, but my impression is that it's pretty low
priority and possibly not considered to be worth the investment.
