On Sun, 09 Jan 2011 11:06:22 -0500, Peter Alexander
<[email protected]> wrote:
I remember there was a discussion a little while back about how Phobos
would assume that structs are cheap to copy, and would simply pass them
by value.
Is this assumption now "the D way"? Should we all just pass structs by
value, assuming cheap copy construction?
The discussion was about assumptions that ranges will make on their
elements. Essentially, ranges will expect their element types to be
cheaply copied.
This does not mean that all structs need be cheaply copyable, nor that
ranges cannot be used with expensive-to-copy element types. It just means
that for the algorithms defined on ranges, the complexity stated depends
on the elements being cheaply copyable.
If so, I think this needs to be documented somewhere (assuming it isn't
already), because it's a radical departure from C++, and also from most
other languages (where everything is a reference type). People need to
be aware of this.
AFAIK, there has not been a conclusion to this. Once there is, if cheap
copy assumption is the result, then I expect documentation to reflect that
(probably at top of std.range and std.algorithm).
-Steve
