From: Hartmut Kaiser (hartmut.kaiser_at_[hidden])
Date: 2006-11-08 19:37:45
Andreas Sæbjørnsen wrote:
> Wow! You are fast! I have experimented a little bit with this
> code and it looks very good, but there are two things which
> needs to be fixed before I can use it:
> * the position of a token in the original source code is
> gone(default in standard Wave)
What do you mean by that?
> * the line positioning is incorrect/non-standard (see
> below for an example).
This does not depend on the Wave library itself, but it's a matter of the
real_positions example. Do you mind to submit a fix for that (I now changed
the sample to output the detailed token information, which makes it easier
to track the output)?
> The column information seems correct to me. But the line
> information is not correct as it does not behave like a
> standard preprocessor which would insert #line directives to
> map the positions to the original source file(s). Example:
> ///BEGIN TEST.C
> #include "test.h"
> #define FOO int x;
>
> int main(){
> FOO; /*comment */double y;
> };
> //END TEST.C
>
> //BEGIN TEST.h
> class Foo{
> };
> //END TEST.h
>
> You would expect the line position of 'double' in test.C line
> 5 to still be 5, but instead it is 6 because
> 1. the line in test.C with just an "\n" in test.C does not
> count in the line positioning (-1 line in position)
> 2. there is no separation between the lines in test.h and test.C
> (+2 lines in position)
The real_positions example does not take into account #line directives, this
could be easily added, though. I simply didn't know, if you need it.
Regards Hartmut
> thanks
> Andreas
> On 11/7/06, Hartmut Kaiser <hartmut.kaiser_at_[hidden]> wrote:
> >
> > Andreas,
> >
> > > I need some advice regarding Wave. What I want to do is
> to operate
> > > with Wave on a token stream and extract the token stream
> > > representing macro calls after expansion. The twist is
> that I want
> > > the token stream after expansion to have the positions
> that another
> > > preprocessor would see on the already expanded output from Wave.
> > > E.g:
> > > #define MACRO_CALL int x;
> > > int main(){
> > > MACRO
> > > };
> > >
> > > Exands into
> > > #line 2
> > > int main(){
> > > int x;
> > > };
> > >
> > > Where 'int x' should have a position of line 3 instead of line 1
> > > after expansion. I also want the column number to
> represent what we
> > > see on line 3 instead of what we see on line 1. Is this possible ?
> >
> > Ok, I've added a new pp hook (what else? :-P) to Wave:
> >
> >
> //////////////////////////////////////////////////////////////////////
> > /////
> > //
> > // The function 'generated_token' will be called by the library
> > whenever a // token is about to be returned from the library.
> > //
> > // The parameter 'ctx' is a reference to the context
> object used for
> > // instantiating the preprocessing iterators by the user.
> > //
> > // The parameter 't' is the token about to be returned
> from the library.
> > // This function may alter the token, but in this case it
> must be //
> > implemented with a corresponding signature:
> > //
> > // Token const&
> > // generated_token(Context const& ctx, Token& t);
> > //
> > // which makes it possible to modify the token in place.
> > //
> > // The default behavior is to return the token passed as the
> > parameter // without modification.
> > //
> >
> //////////////////////////////////////////////////////////////
> /////////////
> > template <typename Context, typename Token>
> > Token const&
> > generated_token(Context const& ctx, Token const& t)
> > { return t; }
> >
> > This should help solving your problem.
> >
> > To show how this hook function may help you I added a new sample
> > 'real_positions' to Wave demonstrating its use. Everything
> is in the
> > Boost CVS::HEAD.
> >
> > HTH
> > Regards Hartmut
> >
> > _______________________________________________
> > Boost-users mailing list
> > Boost-users_at_[hidden]
> > http://listarchives.boost.org/mailman/listinfo.cgi/boost-users
> >
> _______________________________________________
> Boost-users mailing list
> Boost-users_at_[hidden]
> http://listarchives.boost.org/mailman/listinfo.cgi/boost-users