Passing a block to rb_funcall

ruby-talk
1

Oops, just wanted to point out (for future googlers) that I'll have to
tweak this because if no value is passed for the separator, then args[1]
becomes nil. Explicitly passing nil to IO.foreach puts it in paragraph
mode, i.e. this code is the equivalent of IO.foreach(path,nil){ ... } if
no path separator is specified.

I believe this is, yet again, the result of manual argc counting in the
underlying C code. It looks like:

/* rb_io_s_foreach */
if (argc == 1) {
   arg.sep = rb_default_rs;
}

Should instead be:

if(NIL_P(arg.sep))
   arg.sep = rb_default_rs;

That is, unless we *want* nil to mean paragraph mode. I was always
under the impression that only "" (an empty string) would force
paragraph mode.

Regards,

Dan

···

-----Original Message-----
From: nobu.nokada@softhome.net [mailto:nobu.nokada@softhome.net]
Sent: Tuesday, May 31, 2005 9:58 AM
To: ruby-talk ML
Subject: Re: Passing a block to rb_funcall

Hi,

At Wed, 1 Jun 2005 00:35:22 +0900,
Daniel Berger wrote in [ruby-talk:144097]:
> I've seen some mention of rb_iterate, but I wasn't sure how
to apply
> it here.

static VALUE
call_foreach(VALUE args)
{
    return rb_funcall2(rb_cIO, rb_intern("foreach"), 2,
(VALUE *)args); }

static VALUE
yield_block(VALUE val, VALUE block)
{
    return rb_funcall2(block, rb_intern("call"), 1, &val);
}

static VALUE
my_method(int argc, VALUE* argv, VALUE self)
{
    VALUE args[2], block;

    rb_scan_args(argc, argv, "01&", &args[1], &block);
    args[0] = self;

    return rb_iterate(call_foreach, (VALUE)args, yield_block,
block); }

--
Nobu Nakada