# Questions re Method#to\_proc **URL:** \ **Category:** ruby-talk\ **Created:** [18 April 2006 08:39 UTC](https://rubytalk.org/t/questions-re-method-to-proc/26718 "2006-04-18T08:39:51Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![Eli\_Bendersky](https://avatars.discourse-cdn.com/v4/letter/e/3ec8ea/32.png) [@Eli\_Bendersky](https://rubytalk.org/u/Eli_Bendersky)\ **Post date:** [18 April 2006 08:39 UTC](https://rubytalk.org/t/questions-re-method-to-proc/26718/1 "2006-04-18T08:39:51Z")
Hello all, Some things are unclear to me about Method#to\_proc. I understand the following: plus = 12.method("+") p plus.call(13) # prints 25 newplus = plus.unbind.bind(20) p newplus.call(13) # prints 33 Although the usefulness of this eludes me 馃檪 However, this: plus\_proc = plus.to\_proc p plus\_proc.call(10) # prints 10 Is unclear... 1) How does it work ? 2) What does it mean for a Proc to be bound to an object ? 3) Can someone provide an example where it is useful ? 4) Have the 'bind' and 'unbind' methods of Method / UnboundMethod anything in common with Proc#binding or the Binding class ? 5) Have Proc#binding and the Binding class anything in common ? How about Kernel#binding ? Additionally, the following, IMHO demostrates a very surprising and unnatural behavior of to\_proc: def foo(arr)         puts "Got an array with #{arr.length} elements" end # works correctly foo([4, 5, 6]) foo\_proc = method(:foo).to\_proc # throws an ArgumentError: 3 for 1 foo\_proc.call([4, 5, 6]) # works correctly foo\_proc.call([[4, 5, 6]]) The Proc created by to\_proc is obviously different from the original method, since it "folds" its arguments into an array. I guess there will be even more problems when the method receives more than one array as an argument. How should this be handled correctly ? Thanks in advance > **路路路** > > -- > Posted via [http://www.ruby-forum.com/](http://www.ruby-forum.com/). ---
**Author:** ![Yukihiro\_Matsumoto2](https://avatars.discourse-cdn.com/v4/letter/y/b9e5f3/32.png) [@Yukihiro\_Matsumoto2](https://rubytalk.org/u/Yukihiro_Matsumoto2)\ **Post date:** [19 April 2006 15:28 UTC](https://rubytalk.org/t/questions-re-method-to-proc/26718/2 "2006-04-19T15:28:56Z")
Hi, > **路路路** > > In message "Re: questions re Method#to\_proc" on Tue, 18 Apr 2006 17:39:51 +0900, Eli Bendersky \ writes: > > > Additionally, the following, IMHO demostrates a very surprising and > > unnatural behavior of to\_proc: > > > > def foo(arr) > >        puts "Got an array with #{arr.length} elements" > > end > > > > # works correctly > > foo([4, 5, 6]) > > > > foo\_proc = method(:foo).to\_proc > > > > # throws an ArgumentError: 3 for 1 > > foo\_proc.call([4, 5, 6]) > > > > # works correctly > > foo\_proc.call([[4, 5, 6]]) > > This issue will be solved in the future version (1.9), which should > give you the following result: > > Got an array with 3 elements > Got an array with 3 elements > Got an array with 1 elements > >               matz. ---
**Author:** ![Eli\_Bendersky](https://avatars.discourse-cdn.com/v4/letter/e/3ec8ea/32.png) [@Eli\_Bendersky](https://rubytalk.org/u/Eli_Bendersky)\ **Post date:** [19 April 2006 17:14 UTC](https://rubytalk.org/t/questions-re-method-to-proc/26718/3 "2006-04-19T17:14:00Z")
Yukihiro Matsumoto wrote: > \># works correctly > \>foo([4, 5, 6]) > \> > \>foo\_proc = method(:foo).to\_proc > \> > \># throws an ArgumentError: 3 for 1 > \>foo\_proc.call([4, 5, 6]) > \> > \># works correctly > \>foo\_proc.call([[4, 5, 6]]) > > This issue will be solved in the future version (1.9), which should > give you the following result: > > Got an array with 3 elements > Got an array with 3 elements > Got an array with 1 elements > >               matz. Thanks, Matz. By the way, when is 1.9 due ? > **路路路** > > -- > Posted via [http://www.ruby-forum.com/\](http://www.ruby-forum.com/%5C). ---
**Author:** ![Yukihiro\_Matsumoto2](https://avatars.discourse-cdn.com/v4/letter/y/b9e5f3/32.png) [@Yukihiro\_Matsumoto2](https://rubytalk.org/u/Yukihiro_Matsumoto2)\ **Post date:** [19 April 2006 23:01 UTC](https://rubytalk.org/t/questions-re-method-to-proc/26718/4 "2006-04-19T23:01:42Z")
Hi, > **路路路** > > In message "Re: questions re Method#to\_proc" on Thu, 20 Apr 2006 02:14:00 +0900, Eli Bendersky \ writes: > > > By the way, when is 1.9 due ? > > You can fetch it from CVS right now. > >               matz.