[KinoSearch] adding a proximity scorer - Boilerplater

[Marvin Humphrey]

On Jun 16, 2007, at 12:05 AM, Nathan Kurz wrote:

> I'm going with this for now, which seems reasonable to me:
>
> /* ADOPT is an alternative to CREATE for a subclass contructor that  
> wants to
>   start where  the parent constructor left off.  For example:
>      SubClass *SubClass_new(parent_args, new_arg) {
>         ADOPT(self, Parent_new(parent_args), SubClass, SUBCLASS);
> 	 self->var = new_arg;
> 	 return self;
>      }
> */
> #define ADOPT(var, instance, type, vtable) \
>        type *var = (type *) (instance);            \
>        var->_ = &(vtable);                         \
>        var = KINO_REALLOCATE(var, 1, type);
>
> Does it seem like this would work?

Your approach is probably cleaner than the one I've taken, which has  
been to create two functions: Parent_new() and Parent_init_base().

An example taken from BitVector is pasted below my sig.  DelDocs,  
which is a subclass of BitVector, supplies its own memory chunk to  
BitVec_init_base() instead of reallocating an instance returned by  
BitVec_new() -- avoiding the expense of double allocation.

However, I can see doing things your way by default, then going to  
the two-function setup only for performance-critical constructors.   
There aren't very many of those -- and DelDocs_new() probably isn't  
one of them. :)

What I really want to do, though, is figure out how to implement KS  
objects using the inside-out object model.  I believe that this is  
the key to realizing the goals I've laid out for subclassing Scorer.

   int
   SubClass_new(parent_args, new_arg) {
      int me = Parent_new(parent_args);
      allocate_and_store(me, new_arg);
      return me;
   }

It can't be quite so simple, but that's the general idea.

Marvin Humphrey
Rectangular Research
http://www.rectangular.com/