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From: "Norman Jonas" <normanjonas@arcor.de>
To: <gcc@gcc.gnu.org>
Subject: Re: Re: c++ "with" keyword
Date: Sun, 29 Dec 2002 08:32:00 -0000
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I think you missed the point. The reason for the with keyword is not to use
a pointer but to leave
the long structs name which is not done by your example :

struct S
{
    char* name;
    char* street;
    char* city;
} verylongdescriptivename;

If you want to access several values of this struct you always have to type
in the whole name :

verylongdescriptivename.name = "hans";
verylongdescriptivename.street = "xxx 13";
verylongdescriptivename.city = "cologne";

using the "with" keyword this code becomes much smaller and cleaner :

with ( verylongdescriptivename )
{
    .name = "hans";
    .street = "xxx 13";
    .city = "cologne";
}

( It is possible to use a pointer with a very short, undescriptive name, but
that makes the
code unreadable and stupid ( variables should have explanative names, not a
confusing x* )

Norman

> erik wrote :
>
> The example
>
>  struct S
>  {
>      int x;
>      int y;
>  };
>
>  int main()
>  {
>      S s;
>      with (s)
>      {
>          .x = 1;
>          .y = 2;
>      }
>      return 0;
>  }
>
> can easily be rewritten by introducing temporary references, as in
>
>  int main()
>  {
>      S s;
>      {
>          S& t = s;
>          t.x = 1;
>          t.y = 2;
>      }
>      return 0;
>  }
>
> This requires only one additional variable reference each time the
> "with" object is used.  Additionally, it allows several "with" objects
> (with different names) at the same time.  In C, the same thing can be
> done by using pointers.
>
> -erik