Dynamically set local variables in Ruby

Question

I'm interested in dynamically setting local variables in Ruby. Not creating methods, constants, or instance variables.

So something like:

args[:a] = 1
args.each_pair do |k,v|
  Object.make_instance_var k,v
end
puts a
> 1

I want locally variables specifically because the method in question lives in a model and I dont want to pollute the global or object space.

Answer 1

As an additional information for future readers, starting from ruby 2.1.0 you can using binding.local_variable_get and binding.local_variable_set:

def foo
  a = 1
  b = binding
  b.local_variable_set(:a, 2) # set existing local variable `a'
  b.local_variable_set(:c, 3) # create new local variable `c'
                              # `c' exists only in binding.
  b.local_variable_get(:a) #=> 2
  b.local_variable_get(:c) #=> 3
  p a #=> 2
  p c #=> NameError
end

As stated in the doc, it is a similar behavior to

binding.eval("#{symbol} = #{obj}")
binding.eval("#{symbol}")