From: Ross Bamford <rosco@...>
Date: 2006-12-29T22:00:06+09:00
Subject: Re: How to do Hash#each_pair from C extension?

On Fri, 29 Dec 2006 08:22:34 -0000, Bill Kelly <billk@cts.com> wrote:

> Hi,
>
> I'm trying to copy all the key/value pairs from a Ruby
> hash into an STL hash.  (BTW, I'm using Ruby 1.8.4 and
> cannot change the ruby version easily.)
>
> It looks like rb_hash_foreach() in hash.c does exactly
> what I want--allows me to pass in a function pointer,
> which it will invoke yielding each key/value pair--but
> it's declared static in hash.c.
>
> I looked at duplicating that functionality in my own
> C code, but it requires "st.h" as well as constants
> such as HASH_DELETED which are defined privately in
> hash.c.
>
> Is there a different way I should be going about this?
>

Maybe try something like:

static VALUE hsh_iterfunc(VALUE data_ary, VALUE hsh) {
   VALUE key = rb_ary_entry(data_ary, 0);
   VALUE value = rb_ary_entry(data_ary, 1);

   // do whatever, e.g.
   rb_funcall(rb_mKernel, rb_intern("puts"), 2, key, value);

   return data_ary;
}


VALUE ruby_iterhsh(VALUE self, VALUE hsh) {
   return rb_iterate(rb_each, hsh, hsh_iterfunc, hsh);
}

// ... later,

rb_define_method(cSomeClass, "iterhsh", ruby_iterhsh, 1);



Hope that helps,
Ross

-- 
Ross Bamford - rosco@roscopeco.remove.co.uk