• Prashant V (4/4) Feb 07 2008 I wanted to use D for a simple program just to get a feel for how to use...
• Denton Cockburn (4/11) Feb 07 2008 use ref while indexing:
• Prashant V (6/10) Feb 07 2008 Ah that works great! Thanks. Is there anything similar for variables. Eg...
• Unknown W. Brackets (11/24) Feb 07 2008 You can use the actual & operator...
• Jesse Phillips (5/19) Feb 07 2008 You would have to make test2 a pointer.
• Don Clugston (3/16) Feb 08 2008 Not at present, but IIRC it is an intended future feature (with syntax e...

Prashant V <dmd prashantv.com> writes:

I wanted to use D for a simple program just to get a feel for how to use it,
and while overall it was pretty easy, I found an annoying problem that I could
not find an answer to online.

I want to be able to iterate through an array, and I want the current element
to be the actual struct in the array itself. At the moment, it looks like the
foreach is making a copy of the struct in the array so any changes are not made
to the original in the array.

Is there any way to tell D to specifically give me the referenced variable
rather than a copy? I had to resort to using for with an index, and I don't
really think that is an ideal solution.

I want to know if there is a D syntax for the & reference modifier in C++.

Denton Cockburn <diboss hotmail.com> writes:

Prashant V Wrote:

 I wanted to use D for a simple program just to get a feel for how to use it,
and while overall it was pretty easy, I found an annoying problem that I could
not find an answer to online.
 
 I want to be able to iterate through an array, and I want the current element
to be the actual struct in the array itself. At the moment, it looks like the
foreach is making a copy of the struct in the array so any changes are not made
to the original in the array.
 
 Is there any way to tell D to specifically give me the referenced variable
rather than a copy? I had to resort to using for with an index, and I don't
really think that is an ideal solution.
 
 I want to know if there is a D syntax for the & reference modifier in C++.

use ref while indexing:

foreach (ref s; structs)
   // do something

Prashant V <dmd prashantv.com> writes:

Denton Cockburn Wrote:
 use ref while indexing:
 
 foreach (ref s; structs)
    // do something

Ah that works great! Thanks. Is there anything similar for variables. Eg can I
go

int test = 5;
ref auto test2 = test;
test++;

and have the change reflected in test?

"Unknown W. Brackets" <unknown simplemachines.org> writes:

You can use the actual & operator...

	int a = 5;
	auto b = &a;

	writefln("a: %s, b: %s", a, *b);

And there's also this, but it's not exactly the same thing (it literally 
is just an aliased variable name):

	int a = 5;
	alias a b;

	writefln("a: %s, b: %s", a, b);

-[Unknown]


Prashant V wrote:
 Denton Cockburn Wrote:
 use ref while indexing:

 foreach (ref s; structs)
    // do something

 
 Ah that works great! Thanks. Is there anything similar for variables. Eg can I
go
 
 int test = 5;
 ref auto test2 = test;
 test++;
 
 and have the change reflected in test?

Jesse Phillips <jessekphillips gmail.com> writes:

On Fri, 08 Feb 2008 00:21:01 -0500, Prashant V wrote:

 Denton Cockburn Wrote:
 use ref while indexing:
 
 foreach (ref s; structs)
    // do something

 
 Ah that works great! Thanks. Is there anything similar for variables. Eg
 can I go
 
 int test = 5;
 ref auto test2 = test;
 test++;
 
 and have the change reflected in test?

You would have to make test2 a pointer.

int test = 5
auto test2 = &test
(*test2)++;

Don Clugston <dac nospam.com.au> writes:

Prashant V wrote:
 Denton Cockburn Wrote:
 use ref while indexing:

 foreach (ref s; structs)
    // do something

 
 Ah that works great! Thanks. Is there anything similar for variables. Eg can I
go
 
 int test = 5;
 ref auto test2 = test;
 test++;
 
 and have the change reflected in test?

Not at present, but IIRC it is an intended future feature (with syntax exactly 
as you've written).