RE: [boost] Wave and flex_string [was: Re: Wave C++ Review BeginsToday...]

From: Hartmut Kaiser (HartmutKaiser_at_[hidden])
Date: 2005-02-12 02:38:46

Reece Dunn wrote:

> >>I think Wave should become part of Boost.
> 
> I agree. It is an invaluable tool. 

Thanks!

> This would especially be 
> the case if:
> 1.  There is a wave.jam toolset for BBv2.
> 2.  It is easy to chain wave in the build process. That is:
> 
> exe demo : main.cpp ; # compiler preprocessor
> exe demo : main.cpp : <preprocessor>wave ; # wave preprocessor

Great idea! 
Unfortunately I'm not an expert in BBv2, so somebody else will have to take
this...

> > This was discussed already on this list in conjunction with 
> the dicussion
> > about the const_string library. I don't know, what's the 
> current status, but
> > IIRC there were some people interested in putting together 
> several different
> > string implementations compatible with std::string et.el.
> 
> I have been working on this using a variant of flex_string for my 
> fixed_string class because flex_string does not handle the way I am 
> implementing flex_string.
> 
> One issue I have with flex_string is that it is too big. 
> Granted, that 
> is because the std::string definition is big as well. Given 
> this, I have 
> been factoring out the various methods into groups (iterator, element 
> access, etc.)
> 
> The new approach makes use of the CRTP technique, with the 
> helper macro:
> 
> #define BOOST_CRTP_IMPL(T)\
>           T & derived(){ return *static_cast<T *>(this); }\
>     const T & derived() const{ return *static_cast<const T *>(this); }
> 
> This is more in line with the approach for iterators and can 
> be expanded 
> to include common patterns for container implementations (e.g. with 
> iterators/reverse iterators).
> 
> This would make it easier to use subsets of the std::string 
> interface. 
> For example, Maxim's const_string doesn't use the mutating methods.
> 
> I have also made several modifications to Andrei's flex_string: using 
> Boost's reverse_iterator (for msvc-6.0 support) and the strings 
> char_traits for copy/move/etc. vs using the pod_* methods.

May I try to test Wave with your current implementation(s)?
Where I can find these?

I'm not interested at all to keep and maintain a separate copy of
flex_string (or whatever string class) inside Wave (just for the records:
Wave was successfully tested with several different string implementations,
such as std::string, flex_string and Maxim's const_string - it shouldn't be
a problem to use just another one). As only there is a suitable string class
available in Boost I'll happily change Wave to use this.

Regards Hartmut