• renoX <renosky free.fr> Feb 23 2007
• Bill Baxter <dnewsgroup billbaxter.com> Feb 23 2007

renoX <renosky free.fr> writes:

BCS Wrote:
 davidl wrote:
 
 in c we can print __FUNCTION__ __LINE__ to indicate where we are. in D 
 how  to do, couldn't find.....


 
 __FILE__":"~itoa!(__LINE__)
 
 writef(...)	// at run time
 pragma(msg, ...)// at compile time
 
 Not quite as useful but close.


I disagree about the 'close' part: in C, you wrap __FILE__ or __LINE__ in a
macro, so you have the value of the call site, in D if you put them in a
default argument or in a template you have the current value, not the call site
which is nearly useless..

So let's not beat around the bush, this is an area where (AFAIK) C is superior
to D..

renoX

Bill Baxter <dnewsgroup billbaxter.com> writes:

renoX wrote:
 BCS Wrote:
 davidl wrote:
 in c we can print __FUNCTION__ __LINE__ to indicate where we are. in D 
 how  to do, couldn't find.....



 __FILE__":"~itoa!(__LINE__)

 writef(...)	// at run time
 pragma(msg, ...)// at compile time

 Not quite as useful but close.


 I disagree about the 'close' part: in C, you wrap __FILE__ or __LINE__ in a
macro, so you have the value of the call site, in D if you put them in a
default argument or in a template you have the current value, not the call site
which is nearly useless..
 
 So let's not beat around the bush, this is an area where (AFAIK) C is superior
to D..
 
 renoX


You can use a mixin statement + new compile-time functions so that this 
syntax is possible:

    mixin( Pr("Error!") );

Pr is a char[]function(char[]) that returns a string like:
   `writefln("%s(%s): %s", __FILE__, __LINE__, msg);`

But of course in C you could define your macro so that you can say just 
Pr("Error!"), without needing the extra mixin( ... ) part.  I think 
there will eventually be a shortcut for mixin( ... ).  Maybe #,$,  or 
something.  Then you could have
     $Pr("Error");

--bb