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

9 Nov 2006


      ...
...
* the position of a token in the original source code is
gone(default in standard Wave)
What do you mean by that?
What I need is both the original position and the position from the
real_positions example available on a token.  This makes it possible
to locate a token using the real_positions (which is equivalent to
positions on output from a preprocessor) and then get the original
source code position from that token. Do you see any other way of
achieving this?
...
...
* 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)?
Yes. It was very easy to work with your code so that should be no
problem. Are the real_positions set before or after the tokens are
send to the preprocessing hooks?

Thanks
Andrea
...
...
On 11/7/06, Hartmut Kaiser  wrote:
...
Andreas,
...
I need some advice regarding Wave. What I want to do is
...
...
with Wave on a token stream and extract the token stream
representing macro calls after expansion. The twist is
...
...
the token stream after expansion to have the positions
to operate
that I want
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 
    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
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Re: [Boost-users] [WAVE] position of tokens

Andreas Sæbjørnsen