• Gor Gyolchanyan (25/25) Dec 05 2012 Consider this piece of code:
• Dmitry Olshansky (9/31) Dec 05 2012 I do suspect that template part can only be global (TLS). Then being
• Rene Zwanenburg (5/30) Dec 05 2012 Isn't this an accepts invalid bug?
• =?UTF-8?B?QWxpIMOHZWhyZWxp?= (12/34) Dec 05 2012 That is just a template definition. It is not instantiated in this
• deadalnix (4/29) Dec 05 2012 The compiler should yell at you ! what you try to do here make no

Gor Gyolchanyan <gor.f.gyolchanyan gmail.com> writes:

Consider this piece of code:

struct Test
{
template member(Type)
{
Type member;
}
}

unittest
{
Test test;
test.member!int = 0;
test.member!long = 0;
test.member!short = 0;
import std.stdio; writeln(test.sizeof);
assert(test.sizeof == int.sizeof + long.sizeof + short.sizeof); // fails
assert(test.sizeof == 1); // succeeds
}

I don't get why the structure's size remains unchanged even after
instantiating 3 members inside it.
How can I get the real size of the structure, including all its members
(template or not)?

-- 
Bye,
Gor Gyolchanyan.

Dmitry Olshansky <dmitry.olsh gmail.com> writes:

12/5/2012 12:39 PM, Gor Gyolchanyan пишет:
 Consider this piece of code:

 struct Test
 {
 template member(Type)
 {
 Type member;
 }
 }

 unittest
 {
 Test test;
 test.member!int = 0;
 test.member!long = 0;
 test.member!short = 0;
 import std.stdio; writeln(test.sizeof);
 assert(test.sizeof == int.sizeof + long.sizeof + short.sizeof); // fails
 assert(test.sizeof == 1); // succeeds
 }

 I don't get why the structure's size remains unchanged even after
 instantiating 3 members inside it.
 How can I get the real size of the structure, including all its members
 (template or not)?

I do suspect that template part can only be global (TLS). Then being 
inside of struct is just a visibility thing.

Think of it this way:
how one can put template inside of a fixed-sized instance of Test if 
there can be arbitrary amount of instantiations (and generally unknown 
before compiling all modules that may use it).

-- 
Dmitry Olshansky

"Rene Zwanenburg" <renezwanenburg gmail.com> writes:

On Wednesday, 5 December 2012 at 08:39:12 UTC, Gor Gyolchanyan 
wrote:
 Consider this piece of code:

 struct Test
 {
 template member(Type)
 {
 Type member;
 }
 }

 unittest
 {
 Test test;
 test.member!int = 0;
 test.member!long = 0;
 test.member!short = 0;
 import std.stdio; writeln(test.sizeof);
 assert(test.sizeof == int.sizeof + long.sizeof + short.sizeof); 
 // fails
 assert(test.sizeof == 1); // succeeds
 }

 I don't get why the structure's size remains unchanged even 
 after
 instantiating 3 members inside it.
 How can I get the real size of the structure, including all its 
 members
 (template or not)?

Isn't this an accepts invalid bug?

I don't see how it would be possible to add instance variables to 
a class or struct using templates...

=?UTF-8?B?QWxpIMOHZWhyZWxp?= <acehreli yahoo.com> writes:

On 12/05/2012 12:39 AM, Gor Gyolchanyan wrote:
 Consider this piece of code:

 struct Test
 {
 template member(Type)
 {
 Type member;
 }

That is just a template definition. It is not instantiated in this 
struct for any type.

 }

 unittest
 {
 Test test;

That is an object of an empty struct.

 test.member!int = 0;
 test.member!long = 0;
 test.member!short = 0;

Those lines use a template that is defined inside the struct. They 
instantiate the template for three types. I don't know how the 'member' 
member of the template gets used in this context (it looks like the bug 
that Rene Zwanenburg mentions) but I know that it still has no effect on 
the Test type.

 import std.stdio; writeln(test.sizeof);
 assert(test.sizeof == int.sizeof + long.sizeof + short.sizeof); // fails
 assert(test.sizeof == 1); // succeeds
 }

 I don't get why the structure's size remains unchanged even after
 instantiating 3 members inside it.
 How can I get the real size of the structure, including all its members
 (template or not)?

It does not have any members. One way of injecting members would be to 
use template mixins or string mixins.

Ali

"deadalnix" <deadalnix gmail.com> writes:

On Wednesday, 5 December 2012 at 08:39:12 UTC, Gor Gyolchanyan 
wrote:
 Consider this piece of code:

 struct Test
 {
 template member(Type)
 {
 Type member;
 }
 }

 unittest
 {
 Test test;
 test.member!int = 0;
 test.member!long = 0;
 test.member!short = 0;
 import std.stdio; writeln(test.sizeof);
 assert(test.sizeof == int.sizeof + long.sizeof + short.sizeof); 
 // fails
 assert(test.sizeof == 1); // succeeds
 }

 I don't get why the structure's size remains unchanged even 
 after
 instantiating 3 members inside it.
 How can I get the real size of the structure, including all its 
 members
 (template or not)?

The compiler should yell at you ! what you try to do here make no 
sense :D