From: Joel VanderWerf <vjoel@...>
Date: 2001-12-09T05:48:57+09:00
Subject: [ruby-talk:27976] Re: passing a block from C to Ruby

ts wrote:
> 
> >>>>> "J" == Joel VanderWerf <vjoel@PATH.Berkeley.EDU> writes:
> 
> J> 2. Is there a way I can call a method and indicate to Ruby that the
> J> block associated with it should be the same as the block in the current
> J> context? (This would be more efficient than 1.)
> 
>  See [ruby-talk:21709]
> 
> Guy Decoux

Now that I've looked at rb_obj_call_init, it looks possible to adapt it
to a more general solution. Define a wrapper for rb_funcall2 that
propagates the block by using the PUSH_ITER and POP_ITER macros:

void
rb_funcall2_with_block(obj, meth, argc, argv)
    VALUE obj;
    ID meth;
    int argc;
    VALUE *argv;
{
    PUSH_ITER(rb_block_given_p()?ITER_PRE:ITER_NOT);
    rb_funcall2(obj, meth, argc, argv);
    POP_ITER();
}

I haven't tried this--even if it worked in a simple example, I don't
have enough experience with the Ruby source to know whether this makes
sense in general.

--
Joel VanderWerf                          California PATH, UC Berkeley
mailto:vjoel@path.berkeley.edu                     Ph. (510) 231-9446
http://www.path.berkeley.edu                       FAX (510) 231-9512