# Wish list item: Method#to\_proc **URL:** \ **Category:** ruby-talk\ **Created:** [22 November 2008 23:22 UTC](https://rubytalk.org/t/wish-list-item-method-to-proc/50321 "2008-11-22T23:22:09Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![Roger\_Pack4](https://avatars.discourse-cdn.com/v4/letter/r/bb73d2/32.png) [@Roger\_Pack4](https://rubytalk.org/u/Roger_Pack4)\ **Post date:** [22 November 2008 23:22 UTC](https://rubytalk.org/t/wish-list-item-method-to-proc/50321/1 "2008-11-22T23:22:09Z")
would this be useful/theoretically possible? UnboundMethod#to\_proc Thanks! -=R > **···** > > -- > Posted via [http://www.ruby-forum.com/](http://www.ruby-forum.com/). ---
**Author:** ![Pat\_Nakajima](https://avatars.discourse-cdn.com/v4/letter/p/9fc29f/32.png) [@Pat\_Nakajima](https://rubytalk.org/u/Pat_Nakajima)\ **Post date:** [22 November 2008 23:50 UTC](https://rubytalk.org/t/wish-list-item-method-to-proc/50321/2 "2008-11-22T23:50:52Z")
I put together an implementation here: [rebound/lib/rebound.rb at master · nakajima/rebound · GitHub](http://github.com/nakajima/rebound/tree/master/lib%2Frebound.rb#L11-13%5C). Not great, since it relies on Ruby2Ruby, but it worked for what I needed, which was just to see if I could do it. > **···** > > On Nov 22, 6:22 pm, Roger Pack \ wrote: > > > would this be useful/theoretically possible? > > UnboundMethod#to\_proc > > Thanks! > > -=R > > -- > > Posted viahttp://www.ruby-forum.com/. ---
**Author:** ![a11](https://yyz1.discourse-cdn.com/flex029/user_avatar/rubytalk.org/a11/32/8169_2.png) [@a11](https://rubytalk.org/u/a11)\ **Post date:** [23 November 2008 01:52 UTC](https://rubytalk.org/t/wish-list-item-method-to-proc/50321/3 "2008-11-23T01:52:26Z")
cfp:~ \> cat a.rb class UnboundMethod    def to\_proc this = self      bind(self).to\_proc    end end module M    def m      42    end end include M p M.instance\_method(:m) p M.instance\_method(:m).to\_proc(self).call cfp:~ \> ruby a.rb #\ 42 the issues is, without binding, what is 'self' ??? once bound, to\_proc exists. a @ [http://codeforpeople.com/](http://codeforpeople.com/) > **···** > > On Nov 22, 2008, at 4:22 PM, Roger Pack wrote: > > > would this be useful/theoretically possible? > > UnboundMethod#to\_proc > > Thanks! > > -=R > > -- > we can deny everything, except that we have the possibility of being better. simply reflect on that. > h.h. the 14th dalai lama ---
**Author:** ![Roger\_Pack4](https://avatars.discourse-cdn.com/v4/letter/r/bb73d2/32.png) [@Roger\_Pack4](https://rubytalk.org/u/Roger_Pack4)\ **Post date:** [23 November 2008 02:54 UTC](https://rubytalk.org/t/wish-list-item-method-to-proc/50321/4 "2008-11-23T02:54:36Z")
> cfp:~ \> ruby a.rb > #\ > 42 > > the issues is, without binding, what is 'self' ??? once bound, > to\_proc exists. Cool, though I'll admit I don't understand exactly everything that goes on in there 🙂 My real goal is to be able to share methods from one class to another. I guess one could "share" methods from class to class [if the method originated from a module] by searching ancestor modules for a method and then 'cherry picking' it from the ancestor and including it [?] -=R [http://eigenclass.org/hiki.rb?cmd=view&p=Rename+and+reject+methods+from+included+modules&key=eiffel](http://eigenclass.org/hiki.rb?cmd=view&p=Rename+and+reject+methods+from+included+modules&key=eiffel) > **···** > > -- > Posted via [http://www.ruby-forum.com/\](http://www.ruby-forum.com/%5C). ---
**Author:** ![Pat\_Nakajima](https://avatars.discourse-cdn.com/v4/letter/p/9fc29f/32.png) [@Pat\_Nakajima](https://rubytalk.org/u/Pat_Nakajima)\ **Post date:** [23 November 2008 05:05 UTC](https://rubytalk.org/t/wish-list-item-method-to-proc/50321/5 "2008-11-23T05:05:54Z")
The main issue with this approach is that instances of UnboundMethod can only be bound to objects of the same class on which the method was originally defined. That's why I used Ruby2Ruby. > **···** > > On Nov 22, 8:52 pm, "ara.t.howard" \ wrote: > > > On Nov 22, 2008, at 4:22 PM, Roger Pack wrote: > > > > \> would this be useful/theoretically possible? > > \> UnboundMethod#to\_proc > > \> Thanks! > > \> -=R > > > > cfp:~ \> cat a.rb > > class UnboundMethod > > def to\_proc this = self > > bind(self).to\_proc > > end > > end > > > > module M > > def m > > 42 > > end > > end > > > > include M > > > > p M.instance\_method(:m) > > > > p M.instance\_method(:m).to\_proc(self).call > > > > cfp:~ \> ruby a.rb > > #\ > > 42 > > > > the issues is, without binding, what is 'self' ??? once bound, > > to\_proc exists. > > > > a @[http://codeforpeople.com/](http://codeforpeople.com/) > > -- > > we can deny everything, except that we have the possibility of being > > better. simply reflect on that. > > h.h. the 14th dalai lama ---
**Author:** ![Forum](https://avatars.discourse-cdn.com/v4/letter/f/43a26b/32.png) [@Forum](https://rubytalk.org/u/Forum)\ **Post date:** [23 November 2008 10:46 UTC](https://rubytalk.org/t/wish-list-item-method-to-proc/50321/6 "2008-11-23T10:46:30Z")
> I guess you meant bind( this ).to\_proc > p M.instance\_method(:m).to\_proc(self).call but I guess OP rather wanted     M.i\_m(:m).to\_proc.call( self ) which on a quick thought seems impossible to have ☹ > the issues is, without binding, what is 'self' ??? once bound, to\_proc > exists. It could be provided at call time, see example above. I kinda like the idea. Cheers Robert > **···** > > On Sun, Nov 23, 2008 at 2:52 AM, ara.t.howard \wrote: > > -- > Ne baisse jamais la tête, tu ne verrais plus les étoiles. > > Robert Dober 😉 ---
**Author:** ![a11](https://yyz1.discourse-cdn.com/flex029/user_avatar/rubytalk.org/a11/32/8169_2.png) [@a11](https://rubytalk.org/u/a11)\ **Post date:** [23 November 2008 17:12 UTC](https://rubytalk.org/t/wish-list-item-method-to-proc/50321/7 "2008-11-23T17:12:14Z")
na, just have to perform the late binding in the caller's stead cfp:~ \> cat a.rb class UnboundMethod    def to\_proc      lambda do |this, \*a|        bind(this).to\_proc.call(\*a)      end    end end class Object    def m      42    end end p Object.instance\_method(:m) p Object.instance\_method(:m).to\_proc.call(self) cfp:~ \> ruby a.rb #\ 42 cfp:~ \> other permutations, such as cfp:~ \> cat a.rb class UnboundMethod    def to\_proc      lambda{|\*a| bind(this=self).to\_proc.call(\*a)}    end end class Object    def m() 42 end end p Object.instance\_method(:m) p Object.instance\_method(:m).to\_proc.call cfp:~ \> ruby a.rb #\ 42 which perform automatic late binding of self are also possible/preferrable of course there is the separate issue of what objects an unbound method can be attached to - but i think an orthogonal solution to that, plus something simple like the above, can handle most of the cases. also, ruby19 provides #owner in UnboundMethod, which is useful for this case i think. cheers. a @ [http://codeforpeople.com/](http://codeforpeople.com/) > **···** > > On Nov 23, 2008, at 3:46 AM, Robert Dober wrote: > > > On Sun, Nov 23, 2008 at 2:52 AM, ara.t.howard \> \wrote: > > > > > I guess you meant > > > > bind( this ).to\_proc > > > > > p M.instance\_method(:m).to\_proc(self).call > > > > but I guess OP rather wanted > >    M.i\_m(:m).to\_proc.call( self ) > > > > which on a quick thought seems impossible to have ☹ > > -- > we can deny everything, except that we have the possibility of being better. simply reflect on that. > h.h. the 14th dalai lama ---
**Author:** ![Roger\_Pack4](https://avatars.discourse-cdn.com/v4/letter/r/bb73d2/32.png) [@Roger\_Pack4](https://rubytalk.org/u/Roger_Pack4)\ **Post date:** [1 December 2008 19:53 UTC](https://rubytalk.org/t/wish-list-item-method-to-proc/50321/8 "2008-12-01T19:53:58Z")
Ara Howard 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 > #\ > 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' > **···** > > > On Nov 23, 2008, at 3:46 AM, Robert Dober wrote: > > -- > Posted via [http://www.ruby-forum.com/\](http://www.ruby-forum.com/%5C).