• wjoe (15/15) May 19 2020 As I was reading a few source files of a library I found dozens
• user1234 (5/20) May 19 2020 It has no purpose. In D many attributes are allowed even if they
• wjoe (2/8) May 19 2020 Thank you.
• user1234 (23/32) May 19 2020 A little sample to show you more cases of attributes that have no
• wjoe (2/29) May 20 2020 much appreciated :)

wjoe <invalid example.com> writes:

As I was reading a few source files of a library I found dozens 
of final struct declarations like this:

final struct Foo {

   const pure final nothrow bar() { ... }

}

What's this supposed to express ?

A final class is a class that can't be subclassed - structs can't 
be subclassed, so does that express something else or is the 
final redundant ?
Additionally since it's not possible to subclass a struct it's 
also not possible to override bar() - does 'final bar()' mean 
something else ?

The only relevant bits of my web search for 'dlang: final' were 
results for final class, virtual functions and final switch. Am I 
missing something ?

user1234 <user1234 12.de> writes:

On Tuesday, 19 May 2020 at 10:01:34 UTC, wjoe wrote:
 As I was reading a few source files of a library I found dozens 
 of final struct declarations like this:

 final struct Foo {

   const pure final nothrow bar() { ... }

 }

 What's this supposed to express ?

 A final class is a class that can't be subclassed - structs 
 can't be subclassed, so does that express something else or is 
 the final redundant ?
 Additionally since it's not possible to subclass a struct it's 
 also not possible to override bar() - does 'final bar()' mean 
 something else ?

 The only relevant bits of my web search for 'dlang: final' were 
 results for final class, virtual functions and final switch. Am 
 I missing something ?

It has no purpose. In D many attributes are allowed even if they 
have no meaning.
D-Scanner checks this kind of stuff, to some extent, but not the 
compiler.

wjoe <invalid example.com> writes:

On Tuesday, 19 May 2020 at 10:08:37 UTC, user1234 wrote:
 On Tuesday, 19 May 2020 at 10:01:34 UTC, wjoe wrote:
 [...]

 It has no purpose. In D many attributes are allowed even if 
 they have no meaning.
 D-Scanner checks this kind of stuff, to some extent, but not 
 the compiler.

Thank you.

user1234 <user123 12.de> writes:

On Tuesday, 19 May 2020 at 10:29:51 UTC, wjoe wrote:
 On Tuesday, 19 May 2020 at 10:08:37 UTC, user1234 wrote:
 On Tuesday, 19 May 2020 at 10:01:34 UTC, wjoe wrote:
 [...]

 It has no purpose. In D many attributes are allowed even if 
 they have no meaning.
 D-Scanner checks this kind of stuff, to some extent, but not 
 the compiler.

 Thank you.

A little sample to show you more cases of attributes that have no 
effect:

---
struct Foo
{
     nothrow  nogc int field; // why not ?

     void func()
     {
         void nested() const
         {
             field++;      // mutation is allowed because const is 
a noop
             extern int j; // extern decl in a nested func...
         }

         nothrow i = 8;    // just like auto
         pure f = 9;       // just like auto
          safe s = 10;     // just like auto
          system t = s;    // just like auto
     }
}

void main() { }
---

wjoe <invalid example.com> writes:

On Wednesday, 20 May 2020 at 04:40:33 UTC, user1234 wrote:
 On Tuesday, 19 May 2020 at 10:29:51 UTC, wjoe wrote:
 On Tuesday, 19 May 2020 at 10:08:37 UTC, user1234 wrote:
 [...]

 Thank you.

 A little sample to show you more cases of attributes that have 
 no effect:

 ---
 struct Foo
 {
     nothrow  nogc int field; // why not ?

     void func()
     {
         void nested() const
         {
             field++;      // mutation is allowed because const 
 is a noop
             extern int j; // extern decl in a nested func...
         }

         nothrow i = 8;    // just like auto
         pure f = 9;       // just like auto
          safe s = 10;     // just like auto
          system t = s;    // just like auto
     }
 }

 void main() { }
 ---

much appreciated :)