How to call a method from a different class

ruby-talk
1

Hi all,

I am currently stuck trying to call a method from a different class.

example...

I have a checkout class and within it I have the overall method, I want
to call the overall method from within the shopping class...

Thanks in advance.

···

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Posted via http://www.ruby-forum.com/.

2

So that could be done like this.

<code>
# caveat : untested code
class Checkout

  def overall_instance_method
    "overall total on instance"
  end

  def class.overall_class_method
    "overall total on class"
  end

end

class Shopping

  def order
    # prepare order

    # with a Checkout instance
    checkout = Checkout.new
    puts checkout.overall_instance_method

    # with class method on Checkout
    puts Checkout.overall_class_method
  end

end
</code>

HTH,

Peter

···

On Sat, Dec 10, 2011 at 10:47 PM, Darren H. <dhulem1@umbc.edu> wrote:

Hi all,

I am currently stuck trying to call a method from a different class.

example...

I have a checkout class and within it I have the overall method, I want
to call the overall method from within the shopping class...

3

hey folks,

class methods are defined with `self.foo` rather than `class.foo` - so
that

  def class.overall_class_method
    "overall total on class"
  end

should be written:

  def self.overall_class_method
    "overall total on class"
  end

  Peter's example nicely demonstrates two ways of calling a method
defined in one class from another - either creating an instance of the
first class within the second and then calling the instance method on
it, or by defining the method in the first class as a class method,
rather than an instance method - allowing you to call it directly
without creating an instance of the first class.

  if you make the change noted above, and add...

  s = Shopping.new
  s.order

  ...to the end, you'll see the expected output.

  - j

···

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Posted via http://www.ruby-forum.com/.

4

Sorry for the confusion ... (hits hammer on head: _always_ test code before
posting)

Peter

···

On Sun, Dec 11, 2011 at 2:32 PM, jake kaiden <jakekaiden@yahoo.com> wrote:

hey folks,

class methods are defined with `self.foo` rather than `class.foo` - so
that

def class.overall_class_method
   "overall total on class"
end

should be written:

def self.overall_class_method
    "overall total on class"
end

5

1 module Checkout
  2 extend self
  3
  4 def overall_method
  5 "overall total #{self.class}"
  6 end
  7 end
  8
  9 class Shopping
10 include Checkout
11
12 def order
13 puts overall_method
14 puts Checkout.overall_method
15 end
16 end

overall total Shopping
overall total Module

I just tried this and works D:
I was trying to define one method that i can use
as a class and instance one.

PD: I have to see more often this list :slight_smile:

···

2011/12/11 Peter Vandenabeele <peter@vandenabeele.com>

On Sun, Dec 11, 2011 at 2:32 PM, jake kaiden <jakekaiden@yahoo.com> wrote:

> hey folks,
>
> class methods are defined with `self.foo` rather than `class.foo` - so
> that
>
> def class.overall_class_method
> "overall total on class"
> end
>
> should be written:
>
> def self.overall_class_method
> "overall total on class"
> end
>

Sorry for the confusion ... (hits hammer on head: _always_ test code before
posting)

Peter

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