Beman Dawes wrote:

>  It seems to me the committee (more particularly, the 
>  Evolution Working 
>  Group) is now more willing to seriously consider small changes to the 
>  preprocessor. But unless carefully presented, preprocessor 
>  changes are 
>  still likely to face an uphill battle.
>  
>  To maximize the likelihood of acceptance, consider something 
>  like this:
>  
>  * Implement the feature in Wave, to establish actual implementation 
>  experience. Perhaps keep a note of how much added Wave code 
>  is required.

The implementation of Vesa's proposal in Wave shouldn't be problematic
(__comma__, __lparen__ and __rparen__ with the described behaviour). If
there is sufficient agreement, I'm going to make a first implementation
after finishing the experimental macro scoping stuff, which is under way
right now. I think, that Vesa's proposal may be implemented with
relatively minor effort (about 2-3 days of work and about 100 additional
lines of code).

>  * Let Wave users develop some experience with the feature, to 
>  find out how useful and robust it is in practice.
>  
>  * Iterate the above, if the feature isn't quite right yet.
>  
>  * Do the same for other small PP features.

I'm right now working on the other proposal made recently by Paul
Mensonides. 
These will be available through a new "C++0x" mode: 'wave --c++0x
infile.cpp'

- variadics and placemarkers are already optionally available in C++
mode (through the --variadics command line switch)
- macro scoping should be finished really soon now
- well defined token pasting is already implemented in the new C++0x
mode.

The required effort for the new features is relatively small too. The
expected overall effort for the new features is about 1000 lines of
additional code and 2-3 weeks of work (Wave now consists out of about
14000 loc).

>  * Write a unified proposal to the committee leaning heavily 
>  on the existing 
>  practice that has been developed, with several Boosters as co-authors.

I'm ready to help while writing such a proposal.

Regards Hartmut


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