Inconsistent(?) when including modules

ruby-talk
1

I was playing around with modules when I noticed that
I counld, for example include Math and use sin,cos,etc
as if it were a common method. When I tried to do the
same in irb

module Test
  def Test.triple(x)
     3*x
  end
end

Test.triple 2 => 6

If I include Test from the toplevel
inlcude Test

and then call triple directly I get an error:
irb(main):005:0> triple 2
NoMethodError: undefined method `triple' for
main:Object
        from (irb):5

I then tried to implement the same module as an
extension:

#include <ruby.h>

static VALUE triple(VALUE self, VALUE x){
  return rb_float_new(3.0*NUM2DBL(x));
}

VALUE modulo;

void Init_TestC(){
  modulo = rb_define_module("TestC");
  rb_define_module_function(modulo, "triple", triple,
1);
}
  
When I load this extension,
require 'TestC.so'

TestC.triple 2 => 6

include TestC
triple 2 => 6 # No error

I haven't seen this documented. Can I get this same
behaviour from ruby code or do I need to write an
extension?

Thanks

Paulo Jabardo

···

_______________________________________________________
Yahoo! Acesso Grátis - Internet rápida e grátis.
Instale o discador agora! http://br.acesso.yahoo.com/

2

I was playing around with modules when I noticed that
I counld, for example include Math and use sin,cos,etc
as if it were a common method. When I tried to do the
same in irb

module Test
  def Test.triple(x)
     3*x
  end
end

Test.triple 2 => 6

If I include Test from the toplevel
inlcude Test

and then call triple directly I get an error:
irb(main):005:0> triple 2
NoMethodError: undefined method `triple' for
main:Object
        from (irb):5

I then tried to implement the same module as an
extension:

#include <ruby.h>

static VALUE triple(VALUE self, VALUE x){
  return rb_float_new(3.0*NUM2DBL(x));
}

VALUE modulo;

void Init_TestC(){
  modulo = rb_define_module("TestC");
  rb_define_module_function(modulo, "triple", triple,
1);
}

When I load this extension,
require 'TestC.so'

TestC.triple 2 => 6

include TestC
triple 2 => 6 # No error

I haven't seen this documented. Can I get this same
behaviour from ruby code or do I need to write an
extension?

You ruby module and extension module are not equivalent. Try instead this:

module Test
  def triple(x)
    3*x
  end
  module_function :triple
end

Test.triple 2 # => 6

include Test
triple 2 # => 6

Jason

···

On 7/7/05, Paulo Jabardo <pjabardo@yahoo.com.br> wrote:

Thanks

Paulo Jabardo

_______________________________________________________
Yahoo! Acesso Grátis - Internet rápida e grátis.
Instale o discador agora! http://br.acesso.yahoo.com/

3

Jason Foreman wrote:

I was playing around with modules when I noticed that
I counld, for example include Math and use sin,cos,etc
as if it were a common method. When I tried to do the
same in irb

module Test
  def Test.triple(x)
     3*x
  end
end

Test.triple 2 => 6

If I include Test from the toplevel
inlcude Test

and then call triple directly I get an error:
irb(main):005:0> triple 2
NoMethodError: undefined method `triple' for
main:Object
        from (irb):5

I then tried to implement the same module as an
extension:

#include <ruby.h>

static VALUE triple(VALUE self, VALUE x){
  return rb_float_new(3.0*NUM2DBL(x));
}

VALUE modulo;

void Init_TestC(){
  modulo = rb_define_module("TestC");
  rb_define_module_function(modulo, "triple", triple,
1);
}

When I load this extension,
require 'TestC.so'

TestC.triple 2 => 6

include TestC
triple 2 => 6 # No error

I haven't seen this documented. Can I get this same
behaviour from ruby code or do I need to write an
extension?

You ruby module and extension module are not equivalent. Try instead
this:

module Test
  def triple(x)
    3*x
  end
  module_function :triple
end

Test.triple 2 # => 6

include Test
triple 2 # => 6

It's even simpler:

module Test
  def triple(x)
    3*x
  end
end

extend Test

=> main

triple 2

=> 6

Kind regards

    robert

···

On 7/7/05, Paulo Jabardo <pjabardo@yahoo.com.br> wrote: