On Monday, 22 May 2017 at 10:13:02 UTC, Sebastiaan Koppe wrote:
I work with Scala professionally. I often feel its type
inference for generics/templates is better than D's; as long as
it can find a type _anywhere_ it will use that, no matter where
it needs to pull it from.
Over the past weeks I have been noticing a specific case where
it happens. I call it reverse type inference, simply because it
goes against the normal evaluation order.
While it is only syntactic sugar, I think it would be nice to
have in D and I want to know what you guys think about it.
Some examples:
---
T convert(T)(string s) { ... }
auto dec = "1234".convert!int; // normal
int dec = "1234".convert; // T of convert is inferred
due to type declaration of dec
int square(int t) { ... }
auto a = "1234".convert.square; // since square accepts int, T
of convert is inferred to be int
---
p.s. I am not asking anyone to build it. I just want to have
the idea out there. And if time allows I might take a stab at
implementing it.
AFAICT this should be possible purely with changes to the
compiler frontend (no language changes), yes?
Regardless, this would be nice to have, because imho this (from
your examples):
---
int dec = "1234".convert;
---
is easier to review than this:
---
auto dec = "1234".convert!int;
and I'm all for making code more readable. I must object against
usage of this though:
---
auto a = "1234".convert.square;
---
No way for a reviewer to easily guess the type of a without
inspecting all functions.
