On 2012-07-10 09:04, Jonathan M Davis wrote:
The problem is that map is lazy, so it can't be a random access range, and
sort requires a random access range. If map were eager, it would just be
creating an array anyway. But you don't need to convert it to an array again
after sorting it. sort returns a SortedRange so that functions such as find can
know that it's sorted and take advantage of it, but it sorts in place
(SortedRange is just a wrapper around the range which was passed in and copies
no data), so once you've called sort on your array, it's sorted. You can just
ignore the return type if you're not looking to pass it to a function which
would take advantage of the fact that it's sorted. But since SortedRange
_isn't_ lazy (it's just a wrapper around the newly sorted original range,
after all), it's still a random access range and will work with functions
which require that (unlike map).
You only end up with a range with fewer capabilities than the original when
the algorithm itself intrinsicly requires it, and that sort of range is
generally lazy (since it's more efficient that way, and making it non-lazy would
be equivalent to wrapping it in a call to array anyway).
So it's basically what I said. Sine I want an array as the result of the
operation I do need to convert it to an array again. For my need, it
just seem to be more trouble to use std.algorithm.
--
/Jacob Carlborg
