version(debug)

[Jonathan M Davis]

On Saturday, October 06, 2012 23:49:23 denizzzka wrote:
> I am on dmd 2.060
> 
> debug {} else {} was not obvious for me - I thought that debug is
> a kind of qualifer.

I wouldn't expect you to try either version(debug) or debug {} without seeing 
them in the docs or in TDPL. I suppose that I can see why you would try 
version(debug), but it's not listed in the docs.

There isn't really a debug version of anything in D. What debug {} does is 
it's compiled in when -debug is compiled in, and that can be used in 
conjunction with -release if you want to. So talking about debug vs release in 
D is likely to get very confusing. Rather -debug enables debug blocks which 
are intended for inserting debug code, _not_ code which is meant for non-
release builds.

It looks like version(assert) (which I guess is only in the github version 
right now) will effectively correspond to not having -release, but if there's 
ever a compiler flag which specifically enables or disables assertions instead 
of -release (which does more than just disable assertions - e.g. it disables 
bounds checking in non- at safe code), then it won't actually be guaranteed to 
not be there if -release isn't there. It's close enough though I guess, 
particularly when the type of stuff that you specifically do in non-release code 
is typically the kind of stuff that you want done with assertions are enabled 
and probably wouldn't want enable if assertions were turned off, even if that 
were to somehow happen without -release.

In any case, -debug and debug{} should be explained in the docs somewhere. 
It's certainly not the sort of thing that I would expect you to magically 
know.

- Jonathan M Davis