Ruby - print the variable name and then its value

Question

What is the best way to write a function (or something DSLish) that will allow me to write this code in Ruby. How would I construct the function write_pair?

Answer 1

# make use of dynamic scoping via methods and instance vars
@_binding = binding
def eval_debug(expr, binding = @_binding)
   "#{expr} => #{eval(expr, binding)}"
end

# sample invocation:
x = 10
puts eval_debug "x"
puts eval_debug "x**x"