On Monday, 8 August 2022 at 05:38:31 UTC, 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!
```
this(string type)(ulong number) {
```
You cannot do this.
Instead your type should look like this:
First let's change it up a little bit.
```
struct TestArray(ulong element_n, string type) {
int[element_n] elements;
this(ulong number) {
pragma(msg, "The type is: " ~ typeof(type).stringof);
}
}
```
Now the above will still not work because you do `typeof(type)`
which will always yield string because type is as string and also
the typeof() is not needed in this case and will actually yield
an error.
If it must be a string then you can do it like this:
```
struct TestArray(ulong element_n, string type) {
int[element_n] elements;
this(ulong number) {
mixin("alias T = " ~ type ~ ";");
pragma(msg, "The type is: " ~ T.stringof);
}
}
```
However the ideal implementation is probably this:
```
struct TestArray(ulong element_n, T) {
int[element_n] elements;
this(ulong number) {
pragma(msg, "The type is: " ~ T.stringof);
}
}
```
To instantiate it you simply do:
```
TestArray!(10, "int") val = TestArray!(10, "int")(100);
```
Or
```
TestArray!(10, int) val = TestArray!(10, int)(100);
```
I will recommend an alias to make it easier:
```
alias IntTestArray = TestArray!(10, int);
...
IntTestArray val = IntTestArray(100);
```
