• learnfirst1 (23/23) Aug 08 2018 Why this is a error ?
• learnfirst1 (25/26) Aug 08 2018 this code example can explain what I am try to do here:
• Simen =?UTF-8?B?S2rDpnLDpXM=?= (16/34) Aug 08 2018 __gshared and static need to be initialized with a value known at
• learnfirst1 (6/44) Aug 08 2018 is there a way to pass A a... as alias into template ? so the
• Kagamin (20/20) Aug 09 2018 struct M {
• learnfirst1 (2/22) Aug 09 2018 this is what I want! thanks.

learnfirst1 <learnfirst1 gmail.com> writes:

Why this is a error ?

```
struct S {
         bool v;
         string x;
}

S* add(A...)(ref A a) {
         __gshared s = S(a);
         return &s;
}

void main(){
         auto p = add(true);
}
```

test.d(9): Error: variable _param_0 cannot be read at compile time
test.d(14): Error: template instance `test.add!bool` error 
instantiating
test.d(14): Error: function test.add!bool.add(ref bool _param_0) 
is not callable using argument types (bool)
test.d(14):        cannot pass rvalue argument true of type bool 
to parameter ref bool _param_0



I try pass some into the template to return a __gshared var 
pointer.  the A length is dynamic.

learnfirst1 <learnfirst1 gmail.com> writes:

On Wednesday, 8 August 2018 at 12:57:43 UTC, learnfirst1 wrote:
 Why this is a error ?

this code example can explain what I am try to do here:

struct M {
         int i;
         S*[100] s;
}
struct S {
         M* mp;
         bool x;
}


S* add(A...)(ref A a) {
         __gshared s = S(a);
         alias m = a[0];
         m.s[m.i++] = &s;
         return &s;
}

void main(){
         __gshared M m = M(0);
         __gshared S s = S(&m, false);
         m.s[m.i++] = &s;
         auto p = add(&m, true);  // variable _param_0 cannot be 
read at compile time
}

because S has the optional ctor parameters, I can not use 
template alias param here( some how not work) .

Simen =?UTF-8?B?S2rDpnLDpXM=?= <simen.kjaras gmail.com> writes:

On Wednesday, 8 August 2018 at 12:57:43 UTC, learnfirst1 wrote:
 Why this is a error ?

 ```
 struct S {
         bool v;
         string x;
 }

 S* add(A...)(ref A a) {
         __gshared s = S(a);
         return &s;
 }

 void main(){
         auto p = add(true);
 }
 ```

 test.d(9): Error: variable _param_0 cannot be read at compile 
 time

__gshared and static need to be initialized with a value known at 
compile-time. You're trying to give it a run-time value. You can 
set this after it's first created:

S* add(A...)(ref A a) {
     __gshared S s;
     s = S(a);
     return &s;
}

That's a little kludgy, but apparently that's how it be.

You also get another error message:
 Error: function test.add!bool.add(ref bool _param_0) is not 
 callable using argument types (bool)

That's because add takes its arguments by ref, and true is a 
literal that has no canonical address, and thus can't be passed 
by ref. You might consider using auto ref.

--
   Simen

learnfirst1 <learnfirst1 gmail.com> writes:

On Wednesday, 8 August 2018 at 13:13:42 UTC, Simen Kjærås wrote:
 On Wednesday, 8 August 2018 at 12:57:43 UTC, learnfirst1 wrote:
 Why this is a error ?

 ```
 struct S {
         bool v;
         string x;
 }

 S* add(A...)(ref A a) {
         __gshared s = S(a);
         return &s;
 }

 void main(){
         auto p = add(true);
 }
 ```

 test.d(9): Error: variable _param_0 cannot be read at compile 
 time

 __gshared and static need to be initialized with a value known 
 at compile-time. You're trying to give it a run-time value. You 
 can set this after it's first created:

 S* add(A...)(ref A a) {
     __gshared S s;
     s = S(a);
     return &s;
 }

 That's a little kludgy, but apparently that's how it be.

 You also get another error message:
 Error: function test.add!bool.add(ref bool _param_0) is not 
 callable using argument types (bool)

 That's because add takes its arguments by ref, and true is a 
 literal that has no canonical address, and thus can't be passed 
 by ref. You might consider using auto ref.

 --
   Simen

is there a way to pass A a... as alias into template ? so the 
code can be just like this:

__gshared S s = S(&m, false);


the binary size is short since in this case the s is static build 
int. and run a bit fast.

Kagamin <spam here.lot> writes:

struct M {
         int i;
         S*[100] s;
}
struct S {
         M* mp;
         bool x;
}

S* add(A...)() {
         alias m = A[0];
         __gshared s = S(&m,A[1..$]);
         m.s[m.i++] = &s;
         return &s;
}

void main(){
         __gshared M m = M(0);
         __gshared S s = S(&m, false);
         m.s[m.i++] = &s;
         auto p = add!(m, true);
}

learnfirst1 <learnfirst1 gmail.com> writes:

On Thursday, 9 August 2018 at 13:42:03 UTC, Kagamin wrote:
 struct M {
         int i;
         S*[100] s;
 }
 struct S {
         M* mp;
         bool x;
 }

 S* add(A...)() {
         alias m = A[0];
         __gshared s = S(&m,A[1..$]);
         m.s[m.i++] = &s;
         return &s;
 }

 void main(){
         __gshared M m = M(0);
         __gshared S s = S(&m, false);
         m.s[m.i++] = &s;
         auto p = add!(m, true);
 }

this is what I want! thanks.