[swift-evolution] Epic: Typesafe calculations

[Dave Abrahams]

on Wed Jan 13 2016, Thorsten Seitz via swift-evolution <swift-evolution-m3FHrko0VLzYtjvyW6yDsg-AT-public.gmane.org> wrote:

>> Am 13.01.2016 um 00:06 schrieb Dave Abrahams
>> <dabrahams at apple.com>:
>> 
>>> On Jan 7, 2016, at 10:46 AM, Thorsten Seitz
>>> <tseitz42 at icloud.com> wrote:
>
>>> 
>>> Really great to hear that you are planning for Swift to be able to
>>> do these kinds of things!
>>> 
>>> I tried to see how far I could get (working from memory of a
>>> Haskell library; Boost.Units seems quite similar at first glance),
>>> but failed of course because of the missing parameterized recursive
>>> typealiases:
>> 
>> Sadly, the lack of the ability to define a pretty shorthand for
>> quantities is not what stands in the way, fundamentally.
>
> I'm afraid I don't get your meaning here. Would you mind to explain a bit more?
> Thanks!

Typealiases are just about creating new names for existing types.  The
inability to even form the correct type when an an acceleration is
multiplied by a time is the more fundamental issue.  You need to add
corresponding powers of the fundamental dimensions.

HTH,

-Dave