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\"          


        

Answer 1

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