dynamic_constant_lookup

📦 Dynamic Constant Lookup and Instantiation

Ruby’s const_get, const_defined?, and const_set let you reference or create constants by name at runtime. This is useful for plugin systems, dynamic class loading, or namespaced configurations. Always verify existence with const_defined? to avoid NameError.

module Vehicles; class Car; end; end

def build_vehicle(type)
  namespace = Vehicles
  if namespace.const_defined?(type)
    klass = namespace.const_get(type)
    return klass.new
  else
    raise "Unknown vehicle #{type}"
  end
end

car = build_vehicle("Car")  #=> #<Vehicles::Car:0x0000...>