From: Patrick Hurley <phurley@...>
Date: 2006-09-08T00:43:02+09:00
Subject: Re: Has a method been called?

On 9/7/06, Jan Svitok <jan.svitok@gmail.com> wrote:
> On 9/7/06, aidy <aidy.rutter@gmail.com> wrote:
> > Hi,
> > Is it possible to find out if a method has been called except by adding
> > a flag to it?
> >
> > class Whatever
> >   @flag = 0
> >
> >   def method_called
> >     @flag += 1
> >   end
> >
> >   def has_method_been_called
> >     false
> >     return true if @flag > 0
> >   end
> >
> > end
> >
> > Cheers
> >
> > Aidy
>
> If it's enough for you to know that off-line, you can use rcov or
> ruby-prof for that. Run rcov and see whether it's code was visited. If
> you need to know in the runtime, that's another story ;-)
>
>

You can also whip up a little meta programming mess (warning thrown
together, collision causing, not thread safe code follows):

class Module

  def flag_use(sym)
    self.instance_eval do
      define_method "#{sym}_called?" do
        false
      end

      flag_name = "use_flagged_#{sym}".to_sym
      alias_method flag_name, sym
      define_method sym do
        self.class.instance_eval do
          alias_method sym, flag_name
          define_method "#{sym}_called?" do
            true
          end
        end
        flag_name
      end
    end
  end
end

Then...

class Foo
  def bar
    puts :bar
  end
  flag_use :bar
end

f = Foo.new
p f.bar_called?
f.bar
p f.bar_called?

pth