Multiple return values...

[Andrei Alexandrescu]

On 3/9/12 3:59 PM, Timon Gehr wrote:
> Yes, but we wouldn't have needed it if the built-in one would have been
> considered sufficient.

The goal is considering the language sufficient for implementing a 
useful structure such as Tuple in a library. Same goes about associative 
arrays.

> - Returning it from a function is not efficient.

Implementation issue, if at all. Solving that will optimize the return 
of any structure in any D code.

> - It does not play very nicely with type deduction.

It plays by the rules enacted by the D programming language. If those 
aren't nice, there's a problem with them rules. If you like them rules 
but want "special" rules for templates, you're asking for magic. Magic 
smells.

> - It has clumsy syntax and is therefore rarely used.

Then templates have clumsy syntax and therefore are rarely used.

> Notably, there is no convenient unpacking syntax. Walter does not merge
> the patches of Kenji Hara that would fix this because presumably he
> fears it could get in the way of a more general solution.

This is because we need to think about that stuff to maximize its 
generality.

> - It is a trivial wrapper for an underpowered built-in type. This causes
> confusion.

It's not quite trivial.

> This situation is neither particularly pragmatic nor pure enough. I'd
> call it a wart.

I'd call it a great artifact. Love the Tuple (and the Drake).


Andrei