Why are fixed length arrays passed by value while variable are passed by reference?

[Jacob Carlborg]

On 2013-04-18 15:37, ixid wrote:
> I know this will not be changed, I just want to understand why it is as
> it is.
>
> My naive thought is that consistency is the best scheme and that
> everything should have been passed by value or everything by reference
> unless the user specifies otherwise.
>
> I have read a comment by Andrei that they tried making fixed length
> arrays into reference types but it did not work well. Did the current
> situation arise through the reality of language development or is there
> a reason for the inconsistency?

An array is represent using a struct with a pointer to the array data 
and the length, like this:

struct Array
{
     void* ptr;
     size_t length;
}

The struct is passed by value, but since it contains a pointer to the 
data it will be passed by reference. Note that if you do:

void foo (int[] a)
{
     a ~= 3;
}

auto b = [3, 4];
foo(b);

The caller will not see the change made by "foo".

Don't know if this explanation helped you to understand.

-- 
/Jacob Carlborg