0 cost template instantiation

[Hipreme]

On Thursday, 30 September 2021 at 01:09:47 UTC, Hipreme wrote:
> I have a template function that all it does is given a symbol, 
> it loads a dll for its type + its name:
>
> ```
> void loadSymbol(alias s, string symName = "")()
> {
> 	static if(symName == "")
> 		s = cast(typeof(s))_loadSymbol(_dll, (s.stringof~"\0").ptr);
> 	else
> 		s = cast(typeof(s))_loadSymbol(_dll, (symName~"\0").ptr);
> }
> ```
>
>
> The main problem is that this function is costing 2KB per 
> instantiation, which is something pretty high. Specially if I 
> inline, there is almost no cost when compared to its inline 
> version. Trying to use pragma(inline, true) didn't do anything 
> too.
>
> If I understood correctly, mixin template would be some way to 
> actually inline anything. The problem is that I can't have any 
> kind of expression inside it, so, that's the only way I could 
> think in how to do it.
>
> Optimization seems to don't take care of that behaviour too.
>
> I would like to know which approach could I take for making 
> something like C's #define for that.
>
> As this function could be really rewritten as a macro if I were 
> coding in C, the cost is too high for a function that would be 
> only a syntactic sugar




I could reduce by almost 100kb of code by instead of using the 
former option, I use:

```
void loadSymbols(Ts...)()
{
	static foreach(s; Ts)
		s = cast(typeof(s))_loadSymbol(_dll, s.stringof);
}
```

Then instead of making a call for each one, I just pass a list of 
templates, this would only create one instantiation per need.

I do still don't think that this should be the answer, as the 
alias problem is not yet  solved. It takes a lot of size for 
functions that could be only syntactic sugar, where C would be a 
lot better