RE: [boost] Re: Re: Wave C++ Review Begins Today - February 7, 2005

From: Hartmut Kaiser (HartmutKaiser_at_[hidden])
Date: 2005-02-09 18:03:07

Pavel Vozenilek wrote:

> >> - time_conversion_helper.hpp (don't know where to put it
> >>   but it would come very handy many times)
> >
> > Hmmm... Where does this belong? Any ideas?
> >
> Maybe as small, standalone utility in date-time.

Good idea. Other thought's?

>  ________________________________________________________
> >> Maybe also "expand" pragma could be added, which simply
> >> expands block of code, w/o explaining how.
> >
> > Could you elaborate, please?
> >
> When I want to check how preprocessed source looks like now
> I do things like cl /E xyz.cpp and then search through 
> multimegabyte file.
> 
> If I could have
> 
> ...
> #pragma wave expand
> .. what is here gets expanded but the rest not
> #pragma wave expand-end
> ....
> 
> This would help to avoid these huge files
> when I am not interested in trace output.

Understood.
That will require an additional thought (or two). I'll get back to you on
this, ok?

>  ________________________________________________________
> >>   I would like to have something as my own private
> >>   preprocessor:
> >>
> >> @@ifdef CUSTOMER_X
> >>   ....
> >> @@else
> >>   ....
> >> @@endif
> >>
> >> @@ifdef CUSTOMER_Y
> >> @@include "licensing_info_text"
> >> #include <...>
> >> ...
> >> @@endif
> >>
> >> Could it be described how/whether it can be done with Wawe?
> >> Or maybe even sample.
> >
> > By default Wave respects the standard directive syntax only 
> (starting with 
> > a
> > '#').
> > But you can implement this very easily by providing your own lexing
> > component, which fakes the pp tokens (used internally for #include, 
> > #define
> > etc.) when recognising the @@include, @@define etc. in the 
> input stream.
> >
> Maybe docs could give some hints what is needed
> to touch.

Ok, I'll add a new section about lexer customization, because this seems to
be interesting for several people.

> ________________________________________________________
> One possible feature: would it make sense to have macro as
> __TU_FILE__ which always expands into the name
> of "initially processed file"?
> 
> Say one may like to automatically register modules
> where certain feature is used.
> 
> (No idea how this would play with precompiled headers.)

The name of the translation unit is constant, right? And since wave doesn't
support precompiled headers yet, it shouldn't be a problem at all. And even
Wave will get such a feature added it is possible to keep track of this
predefined macro.
I'll give it an additional thought, but currently I don't see any reason not
to add it to Wave.

Regards Hartmut