On Thursday, 27 January 2022 at 02:49:22 UTC, Andrey Zherikov
wrote:
What is the best way to emulate a default value for template
sequence parameter of a function?
I want something like this:
```d
void foo(MODULES... = __MODULE__)() {}
// these should work:
foo!(module1, module2);
foo!(module1);
foo(); // this should use current module (__MODULE__)
according to default value
```
You can accomplish this by heading off the template sequence
parameter with several default template parameters. If you need
them all under one name, you can recombine them in the function
body with std.meta.AliasSeq, the effective "kind" of a template
sequence parameter.
Example:
```d
void foo(string FirstModule = __MODULE__, RestModules...)() {
alias Modules = AliasSeq!(FirstModule, RestModules);
// things
}
// foo!(module1, module2) => alias Modules = (module1, module2)
// foo!() => alias Modules = (__MODULE__)
```
