On Thu, Dec 22, 2022 at 12:43:28AM +0000, thebluepandabear via Digitalmars-d-learn wrote:
> Say you have the following function that takes in a `ref` parameter:
> 
> ```D
> void modify(ref int num) {
>     num += 5;
> }
> ```
> 
> Does the compiler turn that into the code below?
> 
> ```D
> void modify(int* num) {
>     num += 5;
> }
> ```
> 
> I was just wondering whether or not this is the case because I don't think this was touched in the book about D I am reading.

Yes, a ref parameter is implemented as a pointer in the generated assembly code.  But that's supposed to be an implementation detail that you generally shouldn't worry about unless you're working with low-level operations.


T

-- 
Ph.D. = Permanent head Damage

On 12/21/22 16:43, thebluepandabear wrote:
> Say you have the following function that takes in a `ref` parameter:
>
> ```D
> void modify(ref int num) {
>      num += 5;
> }
> ```
>
> Does the compiler turn that into the code below?
>
> ```D
> void modify(int* num) {
>      num += 5;

Rather:

  *num += 5;

> }
> ```
>
> I was just wondering whether or not this is the case because I don't
> think this was touched in the book about D I am reading.

Yes, references are realized by pointers by CPUs; so that's how the code is compiled as well.

Pointers are considered to be one of the most difficult concepts for beginners (who the book was supposed to target). That's why I tried to hold it off as much as possible. I think once the concept of a reference is understood, pointers should be easy to understand.

That's why I say "Behind the scenes, D's higher-level concepts (class variables, slices, associative arrays, etc.) are all implemented by pointers." only later in the book on the pointers page:

  http://ddili.org/ders/d.en/pointers.html

Ali