Q: How to call parent method explistly?

ruby-talk
1

Is it possible to call parent method specifying method name explicitly
like super.foobar() or parent::foobar()?

    class Parent
       def hello(name)
         puts "Hello #{name}!"
       end
    end

    class Child
      def hello(name)
        # ...
        _hello(name)
        # ...
      end
      private
      def _hello(name)
        # ...
        super(name) # want to call Parent#hello(), not _hello()
        # ...
      end
    end

···

--
regards,
makoto kuwata

2

It's ugly but this works (i assume Child subclasses Parent?)

    class Child < Parent
      def _hello(name)
        Parent.instance_method(:hello).bind(self).call(name)
      end
    end

makoto kuwata wrote in post #983231:

···

Is it possible to call parent method specifying method name explicitly
like super.foobar() or parent::foobar()?

    class Parent
       def hello(name)
         puts "Hello #{name}!"
       end
    end

    class Child
      def hello(name)
        # ...
        _hello(name)
        # ...
      end
      private
      def _hello(name)
        # ...
        super(name) # want to call Parent#hello(), not _hello()
        # ...
      end
    end

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

3

There are a couple of alternatives.

1) Create an alias of the parent's method and call it instead:

class Child < Parent
  alias parent_hello hello
  def _hello(name)
    parent_hello(name)
  end
end

2) use a method object to reference the parent's method:

class Child < Parent
  def parent_hello(*args)
    Parent.instance_method(:hello).bind(self).call(*args)
  end

  def _hello(name)
    parent_hello(name)
  end
end
  
Gary Wright

···

On Feb 22, 2011, at 6:25 PM, makoto kuwata wrote:

Is it possible to call parent method specifying method name explicitly
like super.foobar() or parent::foobar()?

4

Folks, why are you making this so complicated? Nobody mentions the
standard way of doing this by using "super":

class Parent
  def hello_same_args(a)
     puts a
  end

  def hello_different_args
    puts "We don't need args"
  end
end

class Child < Parent
  def hello_same_args(a)
     super
     puts "now in child"
  end

  def hello_different_args(x)
    super()
    puts "Child got #{x}"
  end
end

irb(main):022:0> Child.new.hello_same_args "ARG"
ARG
now in child
=> nil
irb(main):023:0> Child.new.hello_different_args "ARG"
We don't need args
Child got ARG
=> nil

Only if you want to call a _different_ method in the super class you
need to use one of the other approaches. But if you think about it,
usually this is not needed.

Kind regards

robert

···

On Wed, Feb 23, 2011 at 1:09 AM, Gary Wright <gwtmp01@mac.com> wrote:

On Feb 22, 2011, at 6:25 PM, makoto kuwata wrote:

Is it possible to call parent method specifying method name explicitly
like super.foobar() or parent::foobar()?

There are a couple of alternatives.

1) Create an alias of the parent's method and call it instead:

class Child < Parent
alias parent_hello hello
def _hello(name)
parent_hello(name)
end
end

2) use a method object to reference the parent's method:

class Child < Parent
def parent_hello(*args)
Parent.instance_method(:hello).bind(self).call(*args)
end

def _hello(name)
parent_hello(name)
end
end

--
remember.guy do |as, often| as.you_can - without end
http://blog.rubybestpractices.com/

5

Folks, why are you making this so complicated? Nobody mentions the
standard way of doing this by using "super":

[...]

Only if you want to call a _different_ method in the super class you
need to use one of the other approaches. But if you think about it,
usually this is not needed.

The original poster specifically asked about calling a different
method in the parent that was also redefined in the child,
which is why I didn't show the use of super. From the original
message:

  super(name) # want to call Parent#hello(), not _hello()

Gary Wright

···

On Feb 24, 2011, at 3:59 AM, Robert Klemme wrote:

6

Ah, that was the piece I missed. Sorry for the noise.

I'd still question the wisdom of such a design though.

Kind regards

  robert

···

On 24.02.2011 20:25, Gary Wright wrote:

On Feb 24, 2011, at 3:59 AM, Robert Klemme wrote:

Folks, why are you making this so complicated? Nobody mentions the
standard way of doing this by using "super":

[...]

Only if you want to call a _different_ method in the super class you
need to use one of the other approaches. But if you think about it,
usually this is not needed.

The original poster specifically asked about calling a different
method in the parent that was also redefined in the child,
which is why I didn't show the use of super. From the original
message:

   super(name) # want to call Parent#hello(), not _hello()

--
remember.guy do |as, often| as.you_can - without end
http://blog.rubybestpractices.com/