[swift-evolution] Epic: Typesafe calculations

[Dave Abrahams]

on Thu Jan 21 2016, David Waite <david-AT-alkaline-solutions.com> wrote:

>> On Jan 21, 2016, at 1:22 PM, Dave Abrahams via swift-evolution <swift-evolution at swift.org> wrote:
>> 
>> Yes, struct subtyping has come up several times.  There are several
>> things I'd like to do with it in the standard library.
>> 
> What do people mean when they say struct subclassing? Code reuse,
> polymorphism, or something else?

By struct subtyping I mean:

A way to define a partial ordering of relationships between value types,
with implicit conversions from subtype to supertype, and overload
resolution based on a corresponding partial ordering of function/method
overloads (much as it works for generics today).

-Dave