• Mr.Bingo (11/11) Jun 25 2018 One can overload assignment and dispatch so that something like
• aliak (22/33) Jun 25 2018 A.x is translated in to A.opDispatch!"x" with no args. So I guess
• Mr.Bingo (7/48) Jun 25 2018 Ok, for some reason using two different templated failed but
• aliak (19/49) Jun 25 2018 Two opDispatchs as in:

Mr.Bingo <Bingo Namo.com> writes:

One can overload assignment and dispatch so that something like

A.x = ... is valid when x is not a typical member but gets 
resolved by the above functions.

Therefore, I can create a member for assignment. How can I create 
a member for getting the value?

A.x = 3; // Seems to get translated in to A.opDispatch!("x")(3)

works but

foo(A.x); // fails and the compiler says x does not exist


I need something consistent with opDot. I am trying to create 
"virtual"(not as in function) fields and I can only get 
assignment but not accessor.

aliak <something something.com> writes:

On Monday, 25 June 2018 at 13:37:01 UTC, Mr.Bingo wrote:
 One can overload assignment and dispatch so that something like

 A.x = ... is valid when x is not a typical member but gets 
 resolved by the above functions.

 Therefore, I can create a member for assignment. How can I 
 create a member for getting the value?

 A.x = 3; // Seems to get translated in to A.opDispatch!("x")(3)

 works but

 foo(A.x); // fails and the compiler says x does not exist


 I need something consistent with opDot. I am trying to create 
 "virtual"(not as in function) fields and I can only get 
 assignment but not accessor.

A.x is translated in to A.opDispatch!"x" with no args. So I guess 
you can overload or you can static if on a template parameter 
sequence:

import std.stdio;
struct S {
     auto opDispatch(string name, Args...)(Args args) {
         static if (!Args.length) {
             return 3;
         } else {
             // set something
         }
     }
}
void main()
{
     S s;
     s.x = 3;
     writeln(s.x);
}

Cheers,
- Ali

Mr.Bingo <Bingo Namo.com> writes:

On Monday, 25 June 2018 at 13:58:54 UTC, aliak wrote:
 On Monday, 25 June 2018 at 13:37:01 UTC, Mr.Bingo wrote:
 One can overload assignment and dispatch so that something like

 A.x = ... is valid when x is not a typical member but gets 
 resolved by the above functions.

 Therefore, I can create a member for assignment. How can I 
 create a member for getting the value?

 A.x = 3; // Seems to get translated in to A.opDispatch!("x")(3)

 works but

 foo(A.x); // fails and the compiler says x does not exist


 I need something consistent with opDot. I am trying to create 
 "virtual"(not as in function) fields and I can only get 
 assignment but not accessor.

 A.x is translated in to A.opDispatch!"x" with no args. So I 
 guess you can overload or you can static if on a template 
 parameter sequence:

 import std.stdio;
 struct S {
     auto opDispatch(string name, Args...)(Args args) {
         static if (!Args.length) {
             return 3;
         } else {
             // set something
         }
     }
 }
 void main()
 {
     S s;
     s.x = 3;
     writeln(s.x);
 }

 Cheers,
 - Ali

Ok, for some reason using two different templated failed but 
combining them in to one passes:

auto opDispatch(string name, T)(T a)
auto opDispatch(string name)()

Maybe it is a bug in the compiler that it only checks one 
opDispatch?

aliak <something something.com> writes:

On Monday, 25 June 2018 at 15:39:09 UTC, Mr.Bingo wrote:
 On Monday, 25 June 2018 at 13:58:54 UTC, aliak wrote:
 A.x is translated in to A.opDispatch!"x" with no args. So I 
 guess you can overload or you can static if on a template 
 parameter sequence:

 import std.stdio;
 struct S {
     auto opDispatch(string name, Args...)(Args args) {
         static if (!Args.length) {
             return 3;
         } else {
             // set something
         }
     }
 }
 void main()
 {
     S s;
     s.x = 3;
     writeln(s.x);
 }

 Cheers,
 - Ali

 Ok, for some reason using two different templated failed but 
 combining them in to one passes:

 auto opDispatch(string name, T)(T a)
 auto opDispatch(string name)()

 Maybe it is a bug in the compiler that it only checks one 
 opDispatch?

Two opDispatchs as in:

import std.stdio: writeln;
struct S {
     void opDispatch(string name, T)(T t) {
         writeln(t);
     }

     auto opDispatch(string name)() {
         writeln("ret");
         return 4;
     }
}

void main() {
     S s;
     s.x;
     s.x = 4;
}

??

The above seems to work fine. Or maybe you meant something else?