• Jack Applegame (2/20) Nov 16 2020
• Dennis (5/15) Nov 16 2020 Because in-place struct initialization has never been
• Atila Neves (10/20) Nov 16 2020 Nope:
• JN (9/29) Nov 17 2020 Foo foo = {

Jack Applegame <japplegame gmail.com> writes:

Why doesn't it compile?
 auto foo() {
     struct Foo {
         int a, b;
     }
     return Foo({
         a: 10,
         b: 20
     });
 }

Valid C++14:
 auto foo() {
     struct Foo {
         int a, b;
     };
     return Foo({
         .a = 10,
         .b = 20
     });
 }

Dennis <dkorpel gmail.com> writes:

On Monday, 16 November 2020 at 10:22:49 UTC, Jack Applegame wrote:
 Why doesn't it compile?
 auto foo() {
     struct Foo {
         int a, b;
     }
     return Foo({
         a: 10,
         b: 20
     });
 }


Because in-place struct initialization has never been 
implemented. Once the named parameters DIP is implemented, you 
should be able to do that by removing the {}:
https://github.com/dlang/DIPs/blob/master/DIPs/accepted/DIP1030.md

Atila Neves <atila.neves gmail.com> writes:

On Monday, 16 November 2020 at 10:22:49 UTC, Jack Applegame wrote:
 Valid C++14:
 auto foo() {
     struct Foo {
         int a, b;
     };
     return Foo({
         .a = 10,
         .b = 20
     });
 }


Nope:

/tmp % clang++ -c -std=c++14 -pedantic cpp.cpp                    
                                                                   
             1 :(
cpp.cpp:6:13: warning: designated initializers are a C++20 
extension [-Wc++20-designator]
             .a = 10,
             ^
1 warning generated.

JN <666total wp.pl> writes:

On Monday, 16 November 2020 at 10:22:49 UTC, Jack Applegame wrote:
 Why doesn't it compile?
 auto foo() {
     struct Foo {
         int a, b;
     }
     return Foo({
         a: 10,
         b: 20
     });
 }

 Valid C++14:
 auto foo() {
     struct Foo {
         int a, b;
     };
     return Foo({
         .a = 10,
         .b = 20
     });
 }


Foo foo = {
          a: 10,
          b: 20
      }

is working in D at the moment. I can't wait for better 
initialization, named arguments to come into play too.

It's a shame that in some cases C is more expressive than D: 
https://github.com/gfx-rs/wgpu-native/blob/master/examples/triangle/main.c , it
even allows to return a pointer to a struct literal.