Hi, can something like this (I borrowed the C pre-processor idea) be done with variadic mixins?

#define log(variadic-arg)  sys-log("%s:%s" + variadic-arg[0], __FILE__, __LINE__, variadic-arg[1..$]);

I read that mixins can only be used for declarations, and this here is a function call. So wondering, how something like this can be done.

-- 
Robert M. Münch
http://www.saphirion.com
smarter | better | faster

On Wed, 18 Mar 2015 15:35:03 +0100
"Robert M. Münch via Digitalmars-d-learn"
<digitalmars-d-learn@puremagic.com> wrote:

> Hi, can something like this (I borrowed the C pre-processor idea) be done with variadic mixins?
> 
> #define log(variadic-arg)  sys-log("%s:%s" + variadic-arg[0],
> __FILE__, __LINE__, variadic-arg[1..$]);
> 
> I read that mixins can only be used for declarations, and this here is a function call. So wondering, how something like this can be done.
> 

You probably does not need mixins:

module main;
import core.vararg;


void some_fun(char c, string file, int line, ...) {
    import std.stdio : writeln;
    writeln(c, file, line);
}

void log(string file = __FILE__, size_t line = __LINE__, T...)
(T variadic_arg) {
    some_fun(variadic_arg[0],  file, line, variadic_arg[1 .. $]);
}


void main(string[] args)
{
    log('c', 'm', 10);
}

On 2015-03-18 15:27:03 +0000, Daniel Kozák via Digitalmars-d-learn said:

> You probably does not need mixins:
> 
> void log(string file = __FILE__, size_t line = __LINE__, T...)
> (T variadic_arg) {
>     some_fun(variadic_arg[0],  file, line, variadic_arg[1 .. $]);
> }

Hi, ha, forgot about default arguments. Great that this works and take the file & line number where the tempate function is used.

Thanks.

-- 
Robert M. Münch
http://www.saphirion.com
smarter | better | faster