On Thursday, 12 January 2023 at 08:03:34 UTC, John Chapman wrote:
I'm obviously doing something wrong, but don't quite understand.
```d
mixin template helper() {
mixin("writeln(12);");
}
struct Foo {
void opDispatch(string name)() {
import std.stdio;
mixin helper!();
//mixin("writeln(12);");
}
}
void main() {
Foo.init.opDispatch!"bar"();
}
```
The compiler emits these errors about the mixin
("writeln(12);"):
unexpected `(` in declarator
basic type expected, not `12`
found `12` when expecting `)`
no identifier for declarator `writeln(_error_)`
semicolon expected following function declaration
declaration expected, not `)`
Why does the commented code work but the mixin not? Thanks for
any pointers.
Mixin templates cannot have statements directly, so you need two
changes for your code to work:
1. Change your mixin template to something like this:
```d
mixin template helper() {
// we place the statements in this function instead
void helper() {
mixin("writeln(12);");
}
}
```
2. Change the place where you instantiate to this:
```d
struct Foo {
void opDispatch(string name)() {
import std.stdio;
mixin helper!();
helper(); // calling the function in the mixin template
}
}
```
