From: Roger Pack <rogerpack2005@...>
Date: 2008-12-02T04:53:58+09:00
Subject: Re: wish list item: Method#to_proc

Ara Howard wrote:
> On Nov 23, 2008, at 3:46 AM, Robert Dober wrote:
> 
>> but I guess OP rather wanted
>>    M.i_m(:m).to_proc.call( self )
>>
>> which on a quick thought seems impossible to have :-(
> 
> na, just have to perform the late binding in the caller's stead
> cfp:~ > ruby a.rb
> #<UnboundMethod: Object#m>
> 42

Wow that is dang cool.
Next challenge:
getting a method to transfer "easily" from one class to another [not 
directly related classes].  I guess you could do it if the method 
originated from a module--is that the only way?

Ex:

module AddToString
  def yoyo
    'within string func'
  end

end

class String
  include AddToString
end

class Object
 # attempt to find and 'borrow' a method from another class
 # in 1.8, method_name should be a string, in 1.9, not sure
 def borrow_and_run_method(from_this, method_name_desired)
    module_where_found = nil
    for ancestor in from_this.ancestors do
        module_where_found ||= ancestor if ancestor.class == Module && 
ancestor.instance_methods.include?(method_name_desired)
    end
    raise unless module_where_found
    m = Module.new
    m.module_eval { include module_where_found}
    m.instance_methods.each{|method_name| m.module_eval{ 
undef_method(method_name) unless method_name == method_name_desired } }
    # todo: double check we're not overwriting anything...
    self.extend m
    self.send method_name_desired
 end
end

class NoYoYo; end

print NoYoYo.new.borrow_and_run_method(String, 'yoyo') # prints 'within 
string func'
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