Re: [Olena-patches] 694: Add spaces in macros to please icpc. - Olena-patches

4 Nov 2006

Roland Levillain &lt;roland(a)lrde.epita.fr&gt; writes:

...
  /* Icpc chokes when expanding this macro when T is a
template type:
    T is substituted with no additional surrounding space, generating
    a token `>>'.

    G++ has no such problem, but I haven't checked which is the right
    behavior, required by the ISO standard.

    Note that this will no longer be a problem with C++ 0x, since
    expressions like `Foo<Foo<int>>' will be valid.  */ 
Dans le code de CPP on trouve la fonction suivante :

/* Returns nonzero if a space should be inserted to avoid an
   accidental token paste for output.  For simplicity, it is
   conservative, and occasionally advises a space where one is not
   needed, e.g. "." and ".2".  */
int
cpp_avoid_paste (cpp_reader *pfile, const cpp_token *token1,
                 const cpp_token *token2)

--
Utilisée dans l'outputing ici. avoid_paste est de gestion interne.

      /* Subtle logic to output a space if and only if necessary.  */
      if (avoid_paste)
        {
          if (print.source == NULL)
            print.source = token;
          if (print.source->flags & PREV_WHITE
              || (print.prev
                  && cpp_avoid_paste (pfile, print.prev, token))
              || (print.prev == NULL && token->type == CPP_HASH))
            putc (' ', print.outf);
        }
      else if (token->flags & PREV_WHITE)
        putc (' ', print.outf);

Il n'y a pas de commentaire sur le standard dans le code. Je n'ai
d'ailleurs rien trouvé dans les standards. Il y en a un pour CPP ?

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