Re: [boost] [wave] skip include directives

From: Felipe Magno de Almeida (felipe_at_[hidden])
Date: 2006-05-15 18:32:09

On 5/15/06, Hartmut Kaiser <hartmut.kaiser_at_[hidden]> wrote:
>
> Felipe Magno de Almeida wrote:

[snipped]

>
> How do you know that '...when preprocessing different files. Usually they
> will
> > contain the same dependencies...'?

Dont have to be exactly. I'll explain better what I want.
If I have three headers: 'a', 'b' and 'c'.
I want to preprocess 'a' and 'b'.
depends -> has a include directive
'a' depends on 'b' and 'c', and 'b' depends on 'c'.

If I start preprocessing 'b', I want to cache all the analysys I
created for 'b' to be used when preprocessing 'a', without having to
preprocess 'b' all again.
The same applies for 'c' that is include'd directly in 'a' and is used
in 'b', so the analysys for it is already made, I dont need to
preprocess 'c' when preprocessing 'a' *and* preprocessing 'b'.

>
> > This tool should preprocess entire subsets of boost,
> > preprocessing some headers again and again should be really slow.
> > Pragma once wouldnt help here, since I want to cache a
> > preprocessing that would occur inside preprocessing two
> > different files.
>
> IIUC in this case you will even have to switch off Waves #pragma once
> support and the corresponding heuristics because otherwise it won't even
> open a header file for the second time.

No, that wouldn't be necessary. I dont care for the case where one
header will *not* preprocess two times in the same translation file. I
care *only* when preprocessing two different translation files, which
I want to cache the preprocessing of all headers.

> Anyway, it would be really helpful to know, what you're going to do with
> Wave and how. All I've got so far is that you somehow want to analyze
> include file dependencies. Sorry if I've missed this, but is this project
> going to build an extention to the current bcp tool?

I'm doing some research to see if Wave is really useable for creating
a new bcp tool for handling dependencies more accurately. I'm writing
yet the proposal for boost, it is done, but is *really really* weak,
and I'm *very very* late in rewriting the proposal with details of the
project. There are some issues, but in general I cannot see any major
issue for writing it. This tool should, IMO, be usable for handling
dependencies for all toolsets, which is impossible if the whole
environment needs to be available to the tool (e.g. system headers).
Hope you understood what I'm after.

>
> Regards Hartmut

Thanks!
-- 
Felipe Magno de Almeida