From: Lyle Johnson <lyle@...>
Date: 2003-02-19T03:08:52+09:00
Subject: Re: Question about SWIGing a C++ array for Ruby

Glenn M. Lewis wrote:

> I think I solved this one with a hack... in the CSIChart.h file,
> I put:
> =================
> #ifndef SWIG
>   CSITick* ticks;
> #endif
> =================
> and then I added to the RubyStock.i file:
> ========================================================================
> %include "CSIChart.h"
> %extend CSIChart {
>   CSITick* ticks(int index) {
>     while (index < 0) index += self->numticks;  // wrap-around
>     if (index >= self->numticks) {
>       printf("ERROR: index (%d) out of range for ticks array: 0...%d\n",
>              index, self->numticks);
>       return 0;
>     }
>     return &self->ticks[index];
>   }
> };
> ========================================================================
> This works, but is there a way to turn this into a Ruby Array
> so that 'ticks' could be accessed with the '[]' notation?

I think I would change the %extend-ed version of ticks() to look 
something like this instead:

     %extend CSIChart {
       VALUE ticks() const {
         VALUE ary = rb_ary_new();
         for (long i = 0; i < self->numticks; i++) {
           VALUE tickObj =
             SWIG_NewPointerObj(self->ticks[i], SWIGTYPE_p_CSITick, 0);
           rb_ary_push(ary, tickObj);
         }
         return ary;
       }
     };

Hope this helps,

Lyle