On Thursday, 29 May 2014 at 10:28:45 UTC, Chris wrote:
I dug into Chapter 3 about ranges. It clarifies a lot of things about ranges.
Yeah, a lot of the stuff there comes from my own process when writing my first range consuming function (which is still in a pretty ugly form in my sha.d on github, I have never really fixed it).
I had to ask on the newsgroup: what does it really mean to accept a generic input range? Does it mean to attempt data transformations to receive anything? Or is it semi-strict? (the answer is to take any input range but be strict on the element type - don't try to transform it yourself as that introduces bugs and hidden performance issues for the algorithm's user)
I didn't quite understand the answer until some time later and now I think it is fairly simple, but since I was so wrong about it for such a long while I figured other people probably had the same problems and tried to cover them in the book.
One of the sections there talks about emulating random access on a structure that doesn't really support it (a linked list) and focuses on the hidden performance. That's the range-writer side of the same range-consumer rule: don't try to get fancy and support something the underlying data doesn't natively do because then you'll introduce bugs and slowdowns that might be hard to find.
