Ruby ERB String Extensions

erb_string.rb

require 'erb'

class ERBContext
  def initialize(hash)
    hash.each_pair do |key, value|
      singleton_class.send(:define_method, key) { value }
    end
  end

  def get_binding
    binding
  end
end

class ::String
  def erb(assigns = {})
    ERB.new(self).result(ERBContext.new(assigns).get_binding)
  end
end

usage.rb

p "Hello, <%= name %>!".erb(name: "World") # => "Hello, World!"