Re: Serialization (Persistence) library draft submission

From: craigp98072 (craigp98072_at_[hidden])
Date: 2002-03-02 04:50:07

I've been playing around with a serialization library. One thought I 
had was to use a (poor man's) generative approach. Use a macro to 
define the members:

#define SUPPLIER_TYPE_LIST BOOST_PP_TUPLE_TO_LIST( 4, \
  ( DECLARE_MEMBER( S_Num,  num_,     "S#" ), \
    DECLARE_MEMBER( S_Name, name_,    "SName" ), \
    DECLARE_MEMBER( Status, status_,  "Status" ), \
    DECLARE_MEMBER( City,   city_,    "City" ) ))

class Supplier_Tuple
{
  PCLASS(Supplier_Tuple, BOOST_PP_LIST_NIL, SUPPLIER_TYPE_LIST );
public:
  bool operator<(const Supplier_Tuple& rhs) const { return num_ < 
rhs.num_; }
};

At that point, you can customize PCLASS to be anything you want. You 
can declare a special constructor, a static 'create' method, 
describe methods (const and non-const - mine take a templated 
visitor rather than i/o archive), reflective methods, support for 
the named parameter pattern (I haven't tried that one yet), etc.

Note that one reason I define a name for the members is so I can 
integrate with an RDBMS and XML/RPC. They are, in a sense, optional.

--craig

--- In boost_at_y..., "David Abrahams" <david.abrahams_at_r...> wrote:
> Has anyone considered describe /types/ instead of describe methods?
> One very clever system I've seen used globally-declared structure 
instances
> to do this job. I don't remember the details at all, so this could 
be
> completely off-the-mark:
> 
> struct my_record : description<my_record>
> {
>     char const name[] = "my_record";
>     member<int> x;
>     member<int> y;
>     ...
> };
> 
>     ...
> 
> 
> ----- Original Message -----
> From: "Peter Dimov" <pdimov_at_m...>
> To: <boost_at_y...>
> Sent: Friday, March 01, 2002 7:54 AM
> Subject: Re: [boost] Re: Serialization (Persistence) library draft
> submission
> 
> 
> > From: "Vladimir Prus" <ghost_at_c...>
> > > I don't think there's consensus on describe vs. load/save 
question.
> Having
> > > recorded this, I suggest that we postpone this question until 
other
> issues
> > > are resolved.
> >
> > A single describe() method doesn't work for the following 
reasons:
> >
> > 1. const correctness.
> > 2. read/write assymetry.
> > 2a. sequence serialization:
> >
> > template<class R, class T, class A> void read(R & r, 
std::vector<T, A> &
> v,
> > int)
> > {
> >     int m = begin_sequence(r);
> >     v.resize(m);
> >     if(m > 0) read_sequence(r, &v[0], m, 0);
> >     end_sequence(r);
> > }
> >
> > vs
> >
> > template<class W, class T, class A> void write(W & w, 
std::vector<T, A>
> > const & v, int)
> > {
> >     int m = v.size();
> >     begin_sequence(w, m);
> >     if(m > 0) write_sequence(w, &v[0], m, 0);
> >     end_sequence(w, m);
> > }
> >
> > 2b. versioning. When Complex version 1 is serialized as polar 
coordinates
> > but version 2 is cartesian, read/write are assymetric.
> >
> > There probably is a solution to these problems but I haven't 
found it yet
> > ('cause I didn't look that hard.)
> >
> >
> >
> > Info: http://www.boost.org  Send unsubscribe requests to:
> <mailto:boost-unsubscribe_at_y...>
> >
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> >