On Monday, 6 March 2017 at 21:22:46 UTC, Timon Gehr wrote:
On 06.03.2017 21:49, Enamex wrote:
On Monday, 6 March 2017 at 01:37:18 UTC, Andrei Alexandrescu
wrote:
On 3/4/17 10:36 PM, Andrei Alexandrescu wrote:
https://pdfs.semanticscholar.org/5de7/591a853ec947f8de7dc70df0b2ecc38b8774.pdf
I haven't read the paper yet but doesn't that sound exactly
opposite to
what 'sum types' is usually used to mean?
The value of the variable has to be either A or B. If it
stores the
status of both then it's basically a struct, right?
Probably I'm misunderstanding your point on composition and
'joint API'.
I don't think you are. The paper is using non-standard
terminology.
You're right. 'Sum' in that paper joins the interfaces, so it's
really 'product' in the fairly standard type theory terminology.
I wish they hadn't done that, it makes communication harder than
it has to be.
Here's a recent post from our cousins in the Rust belt
http://manishearth.github.io/blog/2017/03/04/what-are-sum-product-and-pi-types/
which may make things clearer to people unfamiliar with that
terminology.
