• ref2401 (2/2) Jan 26 2015 What's the difference between static class and static struct?
• bearophile (8/10) Jan 26 2015 Non-static structs/classes have an extra pointer. Static ones
• Piotrek (4/7) Jan 26 2015 Since when structs have an extra pointer? Maybe you are talking
• anonymous (2/9) Jan 26 2015 Non-static means nested.
• ref2401 (6/6) Jan 27 2015 For several times I've met struct(or static struct) usage in
• Daniel Kozak (5/11) Jan 27 2015 I do not think this is a singleton pattern (no instance). I see
• Daniel Kozak (14/25) Jan 27 2015 import std.stdio;
• ketmar (2/16) Jan 27 2015 blind guess: vmt with "toString()" from Object? ;-)=
• Artur Skawina via Digitalmars-d-learn (6/29) Jan 27 2015 D's `class` magically adds a level of indirection, so C.sizeof
• Piotrek (24/30) Jan 27 2015 You probably saw static member function.
• =?UTF-8?B?QWxpIMOHZWhyZWxp?= (16/32) Jan 27 2015 Of course that includes static member functions, where the 'this'
• Piotrek (5/47) Jan 27 2015 Thanks for comments, Mr. Professor. On duty as usual ;)
• =?UTF-8?B?QWxpIMOHZWhyZWxp?= (5/7) Jan 27 2015 Me too! I browsed the index section to remember the other uses of
• Piotrek (8/18) Jan 27 2015 Hmm,this can be misleading. Nesting in structs doesn't introduce
• =?UTF-8?B?QWxpIMOHZWhyZWxp?= (4/7) Jan 27 2015 You must be thinking of structs nested inside user-defined types.
• Piotrek (8/18) Jan 27 2015 What you wrote about the structs is true. However I was referring
• =?UTF-8?B?QWxpIMOHZWhyZWxp?= (4/16) Jan 27 2015 Makes sense.
• creiglee (11/11) Jul 15 2015 In simple words, Singleton is a pattern and not a keyword. The
• vyarthrot (12/14) Nov 19 2015 In simple words, Singleton is a pattern and not a keyword. The

"ref2401" <refactor24 gmail.com> writes:

What's the difference between static class and static struct?
What should i use?

"bearophile" <bearophileHUGS lycos.com> writes:

On Monday, 26 January 2015 at 14:02:54 UTC, ref2401 wrote:
 What's the difference between static class and static struct?
 What should i use?

Non-static structs/classes have an extra pointer. Static ones 
don't have it, so their differences are the usual ones: a class 
is used by reference and they are often on the heap, while a 
struct is handled by value (or pointer to value). A class has two 
extra hidden fields.

Bye,
bearophile

"Piotrek" <none nowhere.pl> writes:

On Monday, 26 January 2015 at 14:11:32 UTC, bearophile wrote:
 Non-static structs/classes have an extra pointer.

 Bye,
 bearophile

Since when structs have an extra pointer? Maybe you are talking 
about nested structs?


Piotrek

"anonymous" <anonymous example.com> writes:

On Monday, 26 January 2015 at 21:33:10 UTC, Piotrek wrote:
 On Monday, 26 January 2015 at 14:11:32 UTC, bearophile wrote:
 Non-static structs/classes have an extra pointer.

 Bye,
 bearophile

 Since when structs have an extra pointer? Maybe you are talking 
 about nested structs?

Non-static means nested.

"ref2401" <refactor24 gmail.com> writes:

For several times I've met struct(or static struct) usage in 
Phobos for singleton pattern implementation. Unfortunately now i 
can remember only core.runtime.Runtime.
So I've got a question. Why do Phobos guys use struct or static 
struct for or singleton pattern implementation? Why don't use 
static final class for this purpose?

"Daniel Kozak" <kozzi11 gmail.com> writes:

On Tuesday, 27 January 2015 at 09:01:39 UTC, ref2401 wrote:
 For several times I've met struct(or static struct) usage in 
 Phobos for singleton pattern implementation. Unfortunately now 
 i can remember only core.runtime.Runtime.
 So I've got a question. Why do Phobos guys use struct or static 
 struct for or singleton pattern implementation? Why don't use 
 static final class for this purpose?

I do not think this is a singleton pattern (no instance). I see 
it much more like namespace in case of core.runtime.Runtime. And 
yes static final class could do that too but struct looks better 
than final class and you can disable this on structs

"Daniel Kozak" <kozzi11 gmail.com> writes:

On Tuesday, 27 January 2015 at 09:36:49 UTC, Daniel Kozak wrote:
 On Tuesday, 27 January 2015 at 09:01:39 UTC, ref2401 wrote:
 For several times I've met struct(or static struct) usage in 
 Phobos for singleton pattern implementation. Unfortunately now 
 i can remember only core.runtime.Runtime.
 So I've got a question. Why do Phobos guys use struct or 
 static struct for or singleton pattern implementation? Why 
 don't use static final class for this purpose?

 I do not think this is a singleton pattern (no instance). I see 
 it much more like namespace in case of core.runtime.Runtime. 
 And yes static final class could do that too but struct looks 
 better than final class and you can disable this on structs

import std.stdio;
import std.conv;

struct S
{
      disable this();
}

final class C
{
}

void main() {
     writeln(C.sizeof);
     writeln(S.sizeof);
}

ketmar <ketmar ketmar.no-ip.org> writes:

On Tue, 27 Jan 2015 09:40:08 +0000, Daniel Kozak wrote:

 import std.stdio;
 import std.conv;
=20
 struct S {
       disable this();
 }
=20
 final class C {
 }
=20
 void main() {
      writeln(C.sizeof);
      writeln(S.sizeof);
 }

blind guess: vmt with "toString()" from Object? ;-)=

Artur Skawina via Digitalmars-d-learn <digitalmars-d-learn puremagic.com> writes:

On 01/27/15 10:40, Daniel Kozak via Digitalmars-d-learn wrote:
 On Tuesday, 27 January 2015 at 09:36:49 UTC, Daniel Kozak wrote:
 On Tuesday, 27 January 2015 at 09:01:39 UTC, ref2401 wrote:
 For several times I've met struct(or static struct) usage in Phobos for
singleton pattern implementation. Unfortunately now i can remember only
core.runtime.Runtime.
 So I've got a question. Why do Phobos guys use struct or static struct for or
singleton pattern implementation? Why don't use static final class for this
purpose?

 I do not think this is a singleton pattern (no instance). I see it much more
like namespace in case of core.runtime.Runtime. And yes static final class
could do that too but struct looks better than final class and you can disable
this on structs

 
 import std.stdio;
 import std.conv;
 
 struct S
 {
      disable this();
 }
 
 final class C
 {
 }
 
 void main() {
     writeln(C.sizeof);
     writeln(S.sizeof);
 }

D's `class` magically adds a level of indirection, so C.sizeof
gives you just the size of the _reference_.

For the true (ie instance/payload) size you'd have to use 

   __traits(classInstanceSize, C)

artur

"Piotrek" <no_data no_data.pl> writes:

On Tuesday, 27 January 2015 at 09:01:39 UTC, ref2401 wrote:
 For several times I've met struct(or static struct) usage in 
 Phobos for singleton pattern implementation. Unfortunately now 
 i can remember only core.runtime.Runtime.
 So I've got a question. Why do Phobos guys use struct or static 
 struct for or singleton pattern implementation? Why don't use 
 static final class for this purpose?

You probably saw static member function.

Please take the following with a big grain of salt as I took it 
out of my head:
We can divide the D static keyword usage into 3 types:

1. static variable

struct A{int a} // no static before declaration
static A s; //note that static is used for struct variable 
storage class (lifetime)

static int b;
etc.

2. static declaration

static struct A{int a}; //static used for context unnesting
static int fun(){}; // static used also for removing scope context

etc.

3. static if

static if(compile_time_cond)
{
   //this section of code will be taken into the binary, used for 
meta programming
}

I don't think there is much (if any) use of static (type 1) for 
singleton.

Piotrek

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

On 01/27/2015 08:58 AM, Piotrek wrote:

Nice list. :)

 1. static variable

 struct A{int a} // no static before declaration
 static A s; //note that static is used for struct variable storage class
 (lifetime)

 static int b;
 etc.

 2. static declaration

 static struct A{int a}; //static used for context unnesting
 static int fun(){}; // static used also for removing scope context

Of course that includes static member functions, where the 'this' 
pointer is removed.

Actually, "static opCall" is kind of different because it makes the type 
itself callable.

 etc.

 3. static if

 static if(compile_time_cond)
 {
    //this section of code will be taken into the binary, used for meta
 programming
 }

Another use of 'static' that means "at compile time":

static assert

4. Module initialization and deinitialization:

static this
shared static this

static ~this
shared static ~this

5. Module import:

static import std.stdio;

Ali

"Piotrek" <none nowhere.pl> writes:

On Tuesday, 27 January 2015 at 18:18:02 UTC, Ali Çehreli wrote:
 On 01/27/2015 08:58 AM, Piotrek wrote:

 Nice list. :)

 1. static variable

 struct A{int a} // no static before declaration
 static A s; //note that static is used for struct variable

 storage class
 (lifetime)

 static int b;
 etc.

 2. static declaration

 static struct A{int a}; //static used for context unnesting
 static int fun(){}; // static used also for removing scope

 context

 Of course that includes static member functions, where the 
 'this' pointer is removed.

 Actually, "static opCall" is kind of different because it makes 
 the type itself callable.

 etc.

 3. static if

 static if(compile_time_cond)
 {
    //this section of code will be taken into the binary, used

 for meta
 programming
 }

 Another use of 'static' that means "at compile time":

 static assert

 4. Module initialization and deinitialization:

 static this
 shared static this

 static ~this
 shared static ~this

 5. Module import:

 static import std.stdio;

 Ali

Thanks for comments, Mr. Professor. On duty as usual ;)
Let me here thank for your book which I've been reading for some 
time.

Piotrek

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

On 01/27/2015 01:44 PM, Piotrek wrote:

 Let me here thank for your book

I am glad that it is useful.

 which I've been reading for some time.

Me too! I browsed the index section to remember the other uses of 
'static'. :)

Ali

"Piotrek" <no_data no_data.pl> writes:

On Monday, 26 January 2015 at 21:55:19 UTC, anonymous wrote:
 On Monday, 26 January 2015 at 21:33:10 UTC, Piotrek wrote:
 On Monday, 26 January 2015 at 14:11:32 UTC, bearophile wrote:
 Non-static structs/classes have an extra pointer.

 Bye,
 bearophile

 Since when structs have an extra pointer? Maybe you are 
 talking about nested structs?

 Non-static means nested.

Hmm,this can be misleading. Nesting in structs doesn't introduce 
context pointer.

But I agree that if we take into account a hypothetical inferred 
static attribute for "nesting in struct" and the module scope 
cases, then the static and non-static classification looks the 
most suitable.

Piotrek

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

On 01/27/2015 08:33 AM, Piotrek wrote:

 Non-static means nested.

 Hmm,this can be misleading. Nesting in structs doesn't introduce context
 pointer.

You must be thinking of structs nested inside user-defined types. 
Structs that are nested inside functions do have the context pointer.

Ali

"Piotrek" <none nowhere.pl> writes:

On Tuesday, 27 January 2015 at 18:24:29 UTC, Ali Çehreli wrote:
 On 01/27/2015 08:33 AM, Piotrek wrote:

 Non-static means nested.

 Hmm,this can be misleading. Nesting in structs doesn't

 introduce context
 pointer.

 You must be thinking of structs nested inside user-defined 
 types. Structs that are nested inside functions do have the 
 context pointer.

 Ali

What you wrote about the structs is true. However I was referring 
to other thing. I just wanted to emphasize (with my poor English) 
that also classes and structs *nested in struct* doesn't contain 
the additional context pointer. As opposed to class nested in 
class.

Then I think we'd better not say that non-static means nested.

Piotrek

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

On 01/27/2015 01:33 PM, Piotrek wrote:

 On Tuesday, 27 January 2015 at 18:24:29 UTC, Ali Çehreli wrote:
 On 01/27/2015 08:33 AM, Piotrek wrote:

 Non-static means nested.

 Hmm,this can be misleading. Nesting in structs doesn't

 introduce context
 pointer.



Oh, I misread what you wrote. Sorry...

 classes and structs *nested in struct* doesn't contain the additional
 context pointer. As opposed to class nested in class.

 Then I think we'd better not say that non-static means nested.

 Piotrek

Makes sense.

Ali

"creiglee" <creiglee yahoo.com> writes:

In simple words, Singleton is a pattern and not a keyword. The 
Singleton pattern has several advantages over static classes. A 
singleton allows a class for which there is just one, persistent 
instance across the lifetime of an application. That means, it 
created a single instance and that instance (reference to that 
instance) can be passed as a parameter to other methods, and 
treated as a normal object. While a static class allows only 
static methods and and you cannot pass static class as parameter. 
More about.....

http://net-informations.com/faq/netfaq/singlestatic.htm

Lee

vyarthrot <vyarthrot yahoo.com> writes:

On Monday, 26 January 2015 at 14:02:54 UTC, ref2401 wrote:
 What's the difference between static class and static struct?
 What should i use?

In simple words, Singleton is a pattern and not a keyword. The 
Singleton pattern has several advantages over static classes. A 
singleton allows a class for which there is just one, persistent 
instance across the lifetime of an application. That means, it 
created a single instance and that instance (reference to that 
instance) can be passed as a parameter to other methods, and 
treated as a normal object. While a static class allows only 
static methods and and you cannot pass static class as parameter.

Full Source:

http://net-informations.com/faq/netfaq/singlestatic.htm

Vyar