Compile-time global mutables

[Paul Backus]

On Thursday, 30 June 2022 at 13:39:57 UTC, HuskyNator wrote:
> On Thursday, 30 June 2022 at 13:16:48 UTC, Adam Ruppe wrote:
>> If you want to collect a bunch of things and load them at 
>> once, you can use a module constructor; a  `static this` in a 
>> template and the compiler adds them all together.
>
> Not sure I see how that would apply to this example.
> How would you write a static constructor that loads in all 
> files used somewhere in the source code? This seems like a 
> prerequisite to being able to do that.

```d
string[] files;

template register(string file)
{
     static this()
     {
         // TODO: actually load the file
         files ~= file;
     }
     void register() {}
}

void foo()
{
     register!"foo";
}

void bar()
{
     register!"bar";
}

void main()
{
     import std.stdio;
     writeln(files); // ["foo", "bar"]
}
```