Can you eval code in the context of a caller in Ruby?

Question

Essentially I'm wondering if the following can be done in Ruby.

So for example:

def bar(symbol)    # magic code goes here, it outputs "a = 100"  end  def foo   a = 100    bar(:a)  end 

Answer 1

You have to pass foo's context to bar:

def foo   a = 100   bar(:a, binding) end def bar(sym, b)   puts "#{sym} is #{eval(sym.to_s, b)}" end 

Answer 2

There is no built-in way to get a callers binding in Ruby in 1.8.X or 1.9.X.

You can use https://github.com/banister/binding_of_caller to work around.

In MRI 2.0 you can use RubyVM::DebugInspector, see: https://github.com/banister/binding_of_caller/blob/master/lib/binding_of_caller/mri2.rb

Working sample in MRI 2.0:

require 'debug_inspector'  def bar(symbol)   RubyVM::DebugInspector.open do |inspector|     val = eval(symbol.to_s, inspector.frame_binding(2))     puts "#{symbol}: #{val}"   end end  def foo   a = 100   bar(:a) end  foo # a: 100