On Wednesday, 9 September 2015 at 07:19:06 UTC, Bahman Movaqar
wrote:
The only way to make it work is `.array.idup` the output of
`filter`. For example:
auto result = reduce!(
(acc, num) => acc.filter!(
fb => (fb.x < num && fb.y < num) && (fb.x * fb.y > num)
).array.idup
)(foobars, nums);
Honestly, I cannot comprehend anything out of this; why I had
to realise the lazy value and `idup` it for it to become usable
by `reduce`?
Does this mean that I am simply missing something obvious?
Reduce takes the seed, calls your function, and your function
returns a new seed.
What is going wrong is that the types aren't the same. That is,
the type of the seed you supplied - `typeof(foobars)` - isn't the
type that your function returns - `typeof(acc.filter!...)`.
`array()` fixes that, no idea why you need `idup()` though.
OT: I wonder, is reduce able to call a different templated
version of reduce?
