From: "Brian F. Feldman" <green@...>
Date: 2001-09-25T05:56:50+09:00
Subject: [ruby-talk:21648] Re: C++ / Ruby questions again

jglueck@vol.at (=?ISO-8859-1?Q?Bernhard_Gl=FCck?=) wrote:
> ts <decoux@moulon.inra.fr> wrote in message news:<200109241311.f8ODBI620272@moulon.inra.fr>...
> > >>>>> "B" == =?ISO-8859-1?Q?Bernhard Gl=FCck?= <jglueck@vol.at> writes:
> > 
> > B> What the h*** is "#arity" ? Is this a ruby method ? or something else
> > 
> >  Yes. 
> > 
> >   Proc#arity means the instance method arity
> >   Proc::new  means the class method new
> > 
> >  For example, in ruby
> > 
> > pigeon% cat b.rb
> > #!/usr/bin/ruby
> > class A
> >    def a(b, c)
> >    end
> > end
> > 
> > a = A.new
> > am = a.method(:a)
> > p am.arity
> > pigeon% 
> > 
> > pigeon% b.rb
> > 2
> > pigeon% 
> > 
> >  See
> > 
> >   http://www.rubycentral.com/book/ref_c_method.html#arity
> > 
> > 
> > Guy Decoux
> 
> 
> Hm that's a nice thing for ruby. but unfortunatly it does not help
> me... I need to  call a ruby instance method from C++ ... so i need to
> know in C++ how many parameters the ruby instance method i want to
> call takes....
> So the ruby method for doing this does not help me..
> Is there a way of doing the same using the C API ? 

Do you want something more than to call #arity on something from C?  Do you 
need to know it at run-time or compile time?  If at run-time, you can just 
call the arity method.

-- 
 Brian Fundakowski Feldman           \  FreeBSD: The Power to Serve!  /
 green@FreeBSD.org                    `------------------------------'