(I'm deleting an old topic, because my assumptions were wrong.) Can anyone
point me to the latest guidance on using concepts? I believe the documentation
in the manual is out of date. The best guidance I've found is in this RFC:
<https://github.com/nim-lang/RFCs/issues/168>
However, I've having some issues implementing the ideas described there. For
example, suppose I have these concepts:
type
Addable = concept
proc `+`(x, y: Self): Self
Coll[T] = concept
iterator items(x: Self): T
AddableColl[T] = concept
iterator items(x: Self): T
proc `+`(x, y: T): T
Run
In this case, the following works:
proc sum[T: Addable](nums: Coll[T]): T =
for num in nums.items:
result += num
echo @[0, 1, 2].sum
Run
But the following fails, and I'm not sure why:
proc sum[T](nums: AddableColl[T]): T =
for num in nums.items:
result += num
echo @[0, 1, 2].sum
Run
Any help with understanding the second example, as well as the general state of
concepts, would be much appreciated. Thanks.
