Sergey Gromov wrote:
Sun, 25 Jan 2009 13:53:43 -0800, Andrei Alexandrescu wrote:
Christopher Wright wrote:
Andrei Alexandrescu wrote:
Sergey Gromov wrote:
Sat, 24 Jan 2009 17:09:07 -0800, Andrei Alexandrescu wrote:
I'm working on the new range stuff and the range-based algorithm. In
all likelihood, you all might be pleased with the results.
I wanted to gauge opinions on a couple of issues. One is, should the
empty() member function for ranges be const? On the face of it it
should, but I don't want that to be a hindrance. I presume non-const
empty might be necessary sometimes, e.g. figuring out if a stream is
empty effectively means fetching an element off it.
I have a hard time imagining a use for a const range.
Read-only arrays for example.
A range is essentially an iterator. It has to change its internal state
to move to the next element. So a const range will not allow you to
iterate over the members of a const array. It will allow you to iterate
over a single element, either once or an infinite number of times.
A range offering random access can give me any element without the range
actually changing.
This restricts you to algorithms working exclusively with random-access
ranges. Any more generic algos won't work with const ranges. How many
of those do you have?
Stable partition, everything related to binary search, heap functions,
and radial iteration come to mind.
Anyhow, for now let's go with requiring ref returns and we'll see how
that fares.
I'm almost done with std.algorithm. (I am cheating because Walter
emailed me a fixed dmd that allows ref returns from template funs.) Very
exciting. I will post the documentation as soon as I'm done.
Andrei
