On 8/8/22 9:36 AM, Steven Schveighoffer wrote:
On 8/8/22 1:38 AM, rempas wrote:
In the following struct (as an example, not real code):
```
struct TestArray(ulong element_n) {
int[element_n] elements;
this(string type)(ulong number) {
pragma(msg, "The type is: " ~ typeof(type).stringof);
}
}
```
I want to create it and be able to successfully initialize the
template parameters
of the constructor but until now, I wasn't able to find a way to
successfully do
that. Is there a way you guys know? I have tried the following:
```
void main() {
// Doesn't work
auto val = TestArray!(10, "int")(60);
// Doesn't work either
auto val = TestArray!(10).TestArray!("int")(60);
// Neither this works....
auto val = TestArray!(10).this!("int")(60);
}
```
As with every question I make, the solution must be "betterC"
compatible so I can use it.
Thanks a lot!
You cannot explicitly specify template parameters for constructors.
The only true solution is to use a factory function:
```d
TestArray!T testarray(string s, T)(T val) {
... // code that depends on s here
return TestArray!T(...) // call ctor here.
}
```
Just thought of another possibility:
```d
struct StringAnnotated(string s, T)
{
T val;
}
StringAnnotated!(s, T) annotate(string s, T)(T val)
{
return StringAnnotated!(s, T)(val);
}
struct TestArray(ulong element_n)
{
...
this(T)(T val) if (isInstanceOf!(StringAnnotated, T))
{
...
}
}
// use like
TestArray!10(60.annotate!"int");
```
-Steve
