From: William Djaja Tjokroaminata <billtj@...>
Date: 2002-09-06T00:27:57+09:00
Subject: Re: Is It Possible to Create Block from within C?

Hi,

Using "rb_iterate()", it works!  Now, my code looks like

    nextState = nil
    trans.each_key do |key|
        if trans[key] == true
            if nextState.nil? then nextState = key
            else raise_exc ("multiple transitions defined") end
        end
    end
    if nextState.nil?
        ....

There are several problems here.  First, inside the block I need to get
the value of both "trans" and "nextState".  No big deal, I just pack them
into a rb_ary in the last argument of rb_iterate().  Second, I need to get
the value of "nextState" after rb_iterate() finishes.  Probably I can wrap
the pointer of nextState in a BigNum, but it will look too ugly.  The
"best" solution so far is to do array manipulation to get the value of
nextState back.

Is there an easier or standard way of accessing the "logically enclosing
local" variable in a "logical Ruby block" in C, such as for the
"nextState" variable in the code above?

Regards,

Bill
=============================================================================
nobu.nokada@softhome.net wrote:
> To call a method with block:

>     static VALUE
>     statements(VALUE arg, VALUE val)
>     {
>         return block_result;
>     }

>     static VALUE
>     call_func(VALUE obj)
>     {
>         return rb_funcall(obj, rb_intern("func"), 0);
>     }

>     rb_iterate(call_func, obj, statement, 0);