# Binding in ruby1.9

**URL:** <https://www.ruby-forum.com/t/binding-in-ruby1-9/159043>\
**Category:** Ruby\
**Created:** [January 30, 2009, 7:32pm UTC](https://www.ruby-forum.com/t/binding-in-ruby1-9/159043 "2009-01-30T19:32:00Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![timperrett](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/c5a1d2/32.png) [@timperrett](https://www.ruby-forum.com/u/timperrett)\
**Post date:** [January 30, 2009, 7:32pm UTC](https://www.ruby-forum.com/t/binding-in-ruby1-9/159043/1 "2009-01-30T19:32:00Z")

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Could someone explain why this code does not work in ruby1.9 and  
possibly provide a workaround. The end goal is to be able to pass a  
binding to an ERb result method that provides a limited set of  
variables to the ERb template evaluation.

> cat a.rb

obj = Object.new  
class \<\< obj  
attr\_accessor :foo  
end  
obj.foo = ‘the foo method’  
eval “puts foo”, obj. **send** (:binding)

> ruby a.rb  
> the foo method

> ruby1.9 a.rb  
> a.rb:7:in `eval': undefined local variable or method`foo’ for  
> main:Object (NameError)  
> from a.rb:7:in `eval' from a.rb:7:in`’

> ruby1.9 --version  
> ruby 1.9.1p0 (2009-01-30 revision 21907) [i386-darwin9.6.0]

Blessings,  
TwP

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<div class="post-metadata">

**Author:** ![timperrett](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/c5a1d2/32.png) [@timperrett](https://www.ruby-forum.com/u/timperrett)\
**Post date:** [January 30, 2009, 9:00pm UTC](https://www.ruby-forum.com/t/binding-in-ruby1-9/159043/2 "2009-01-30T21:00:40Z")

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Tim P. wrote:

> end  
> obj.foo = ‘the foo method’  
> eval “puts foo”, obj. **send** (:binding)

What an unusual feature to keep coming up.

The contract of binding is that it returns a reification of the caller’s  
binding. Under 1.8, however, the behavior acted a bit differently, using  
the “self” that binding was actually called against. 1.9 has largely  
remedied this by always returning the binding of the caller, even if you  
**send** (:binding) to another object.

I believe instance\_evaling “binding” against the target object would  
give you the behavior you’re looking for:

[headius @ cnutter:~/projects/ruby-benchmark-suite]  
â—† ruby -e “o = Object.new; p o; eval ‘p self’, o. **send** (:binding)”  
#Object:0x29414  
#Object:0x29414  
[headius @ cnutter:~/projects/ruby-benchmark-suite]  
â—† ruby1.9 -e “o = Object.new; p o; eval ‘p self’, o. **send** (:binding)”  
#Object:0x3e736c  
main  
[headius @ cnutter:~/projects/ruby-benchmark-suite]  
â—† ruby1.9 -e “o = Object.new; p o; eval ‘p self’,  
o.instance\_eval{binding}”  
#Object:0x3e72a4  
#Object:0x3e72a4

- Charlie

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<div class="post-metadata">

**Author:** ![timperrett](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/c5a1d2/32.png) [@timperrett](https://www.ruby-forum.com/u/timperrett)\
**Post date:** [January 30, 2009, 9:22pm UTC](https://www.ruby-forum.com/t/binding-in-ruby1-9/159043/3 "2009-01-30T21:22:59Z")

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On Jan 30, 2009, at 12:56 PM, Charles Oliver N. wrote:

> > obj.foo = ‘the foo method’

Okay, that explanation makes sense. My new implementation (following  
along with the Kernel docs)

> cat a.rb  
> obj = Object.new  
> class \<\< obj  
> attr\_accessor :foo  
> def get\_binding() binding; end  
> end  
> obj.foo = ‘the foo method’  
> eval “puts foo”, obj.get\_binding

> ruby1.9 a.rb  
> the foo method

Thanks for the insight.

Blessings,  
TwP

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<div class="post-metadata">

**Author:** ![timperrett](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/c5a1d2/32.png) [@timperrett](https://www.ruby-forum.com/u/timperrett)\
**Post date:** [January 30, 2009, 10:16pm UTC](https://www.ruby-forum.com/t/binding-in-ruby1-9/159043/4 "2009-01-30T22:16:21Z")

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Tim P. wrote:

> eval “puts foo”, obj.get\_binding
> 
> > ruby1.9 a.rb  
> > the foo method

Even better!

- Charlie