Metaprogramming Ruby 2

Kernel#eval

Where you learn that, when it comes right down to it, code is just text.

You already learned about instance_eval and class_eval (in ​instance_eval()​, and ​class_eval()​, respectively). Now you can get acquainted with the third member of the *eval family—a Kernel Method (Kernel Method) that’s simply named eval. Kernel#eval is the most straightforward of the three *eval methods. Instead of a block, it takes a string that contains Ruby code—a Spell: String of Code for short. Kernel#eval executes the code in the string and returns the result:

ctwc/simple_eval.rb

array = [10, 20]
element = 30
eval("array << element")  # => [10, 20, 30]

Executing a literal string of Ruby code is a pretty pointless exercise, but the power of ...