On Mon, 11 Feb 2013 10:26:40 -0500, Dicebot <m.stras...@gmail.com> wrote:
On Monday, 11 February 2013 at 15:06:26 UTC, Steven Schveighoffer wrote:
On Mon, 11 Feb 2013 09:46:54 -0500, Dicebot <m.stras...@gmail.com>
wrote:
This question is so stupid I am just struck with trying to chose the
"good" solution.
Consider this code:
string func(in string[] args)
{
return args.join(" "); // compile error, args is not an input range
}
It is somewhat expected as you can hardly popFront on a const range.
But then question is: how can I wrap const slice into a mutable range
without copying data (using standard language/library solution)? Of
course, I can do .dup.join, but there is no real need to do copy, even
a shallow one.
What you are looking for is a tail-const array:
string func(const(string)[] args)
This will allow traversal, and not allow modification of the elements.
-Steve
No, I do not look for tail const. I don't want to allow head-mutability
for parameter, but I want to make a mutable slice-range for it later.
That does not break any const guarantees and should be safely possible.
in means "const scope". scope is a no-op, const makes the array const,
including the pointer length.
const(T)[] means, the ELEMENTS are const, but the pointer and length can
be changed. This makes it a valid input range.
Since your function is making a copy of the data, this should be fine.
Your explanation is difficult to understand, I'm basically going on what
your code does. If you change "in string[]" to "const(string)[]", the
function should compile.
-Steve
