There are two ways how __FILE__, __LINE__ etc. can se used in function parameters: as regular parameters and as template parameters:

void rt(string file=__FILE__, int line=__LINE__, string func=__FUNCTION__)
{
    writeln(file,"(",line,"): ",func);
}

void ct(string file=__FILE__, int line=__LINE__, string func=__FUNCTION__)()
{
    writeln(file,"(",line,"): ",func);
}

What is recommended way?
What are pros/cons of each case?

On Thu, Oct 22, 2020 at 03:32:57PM +0000, Andrey Zherikov via Digitalmars-d-learn wrote:
> There are two ways how __FILE__, __LINE__ etc. can se used in function parameters: as regular parameters and as template parameters:
[...]
> What is recommended way?
> What are pros/cons of each case?

I don't know what's the "recommended" way, but generally, I prefer to pass them as regular parameters. Otherwise you will get a lot of template bloat: one instantiation per file/line combination.

However, sometimes there is not much choice: if your function is variadic, then you pretty much have to use template parameters, 'cos otherwise you won't be able to pick up the __FILE__/__LINE__ of the caller with default arguments.


T

-- 
Knowledge is that area of ignorance that we arrange and classify. -- Ambrose Bierce

On Thursday, 22 October 2020 at 16:03:45 UTC, H. S. Teoh wrote:
> On Thu, Oct 22, 2020 at 03:32:57PM +0000, Andrey Zherikov via Digitalmars-d-learn wrote:
>> There are two ways how __FILE__, __LINE__ etc. can se used in function parameters: as regular parameters and as template parameters:
> [...]
>> What is recommended way?
>> What are pros/cons of each case?
>
> I don't know what's the "recommended" way, but generally, I prefer to pass them as regular parameters. Otherwise you will get a lot of template bloat: one instantiation per file/line combination.
>
> However, sometimes there is not much choice: if your function is variadic, then you pretty much have to use template parameters, 'cos otherwise you won't be able to pick up the __FILE__/__LINE__ of the caller with default arguments.
>
>
> T

You will. This is possible since v2.079.0 (March 2018): https://dlang.org/changelog/2.079.0.html#default_after_variadic
So yeah, always pass them as function parameters to avoid bloat.

Thanks for all your answers!