On Monday, 12 January 2015 at 16:32:31 UTC, Oleg wrote:
Because dynamic arrays are passed by value to functions. Will it make another copy of array, if I'll pass array by value?
It is important to think of the underlying representation with a pointer and length passed by value. Since it is a pointer, the contents are never copied with a D slice, but reallocation or length changes won't be seen unless it is ref.
In general, I'm skeptical of ref arguments btw because they aren't needed as often as they are used. ref arrays, ref pointers, and ref class objects should only be used if you are going to reassign it to something new (or change the length of the array) and want that seen by the called - the contents are automatically passed by reference.
ref structs are sometimes useful, but even there I tend to avoid them. Value passing is often faster anyway (if the struct.sizeof <= pointer.sizeof it is a win every time, and even if bigger than that it often is) and generally simpler to follow.
So my advice is to break the habit of using ref everywhere in D, you usually don't need it.
