getting line number in templates

[Lutger]

Daniel Ribeiro Maciel wrote:
> Hello!
> 
> I'm wondering if it's possible to design an exception class that would know in which line it ocurred. Without passing __LINE__ argument to it, obviosly.

I have used this template to accomplish something similar:

char[] _enforce(T)(char[] cond, char[] msg)
{
   return std.metastrings.Format!
   (
     `if (!(%s)) throw new %s ("%s: %s (in " ~ %s ~ " at " ~ %s ~ ")";`,
       cond, T.stringof, cond, msg, `__FILE__`, `ToString!(__LINE__)`
   );
}

to use it, instantiate it with a specific exception:

alias _enforce!(XException) xEnforce;

and in code:

mixin(xEnforce(`x > 0 && x < 10`, "out of range"));

The nice thing is that it will reproduce the code you check for an 
exception (`x > 0 && x < 10`), but a mixin is required.

How to get the function string is something that I would like to know 
too, if it's possible. I'd think DMD needs a __FUNCTION__