Re: [Boost-users] [WAVE] position of tokens

From: Andreas Sæbjørnsen (andreas.saebjoernsen_at_[hidden])
Date: 2006-11-09 20:43:46

> > An idea would be to allow calling of generated_token() from
> > one of the other hooks. For instance, if you in
> > rescanned_macro() know when the first macro has been fully
> > texpanded then you can call
> > generated_token() at that point on every token provided to
> > rescanned_macro(). The reason why I say first macro is that a
> > macro in it's formal definition can call another macro, so
> > first macro calls second macro etc.
> >
> > The suggestion I made above can probably also be considered
> > an optimization (?) because you could also imagine
> > recomputing the correct positions on every call to rescanned_macro.
> > Do you see any reason for this not working?
>
> If the generated_token() gets call for instance in the rescanned_macro()
> hook you won't be able to track the resulting position of the token because
> it's impossible to tell, at which expansion level inside a macro the current
> token got generated. Do I miss something?

You know that for each call to the hook expand_*_like_macro() there is
one call to rescanned_macro(), so by using this information I think
that you can know the epansion level. In order to avoid multiple calls
to generated_token() it is possible to set a bit in the token which
tells that it was already set or maybe the correct positions should be
negative to begin with(?). Do you see any problems with such an
approach?

>
> Regards Hartmut
>
>
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