module Traject::QualifiedConstGet

From redcorundum.blogspot.com/2006/05/kernelqualifiedconstget.html Adapted into a module, rather than monkey patching it into Kernel

Method to take a string constant name, including

qualifications, and

look up the actual constant. Looks up relative to current file. Respects leading ::. Etc.

class Something
  include Traject::QualifiedConstGet

  def foo
    #...
    klass = qualified_const_get("Foo::Bar")
    #...
  end
end

Public Instance Methods

qualified_const_get(str) click to toggle source
# File lib/traject/qualified_const_get.rb, line 20
def qualified_const_get(str)
  path = str.to_s.split('::')
  from_root = path[0].empty?
  if from_root
    from_root = []
    path = path[1..-1]
  else
    start_ns = ((Class === self)||(Module === self)) ? self : self.class
    from_root = start_ns.to_s.split('::')
  end
  until from_root.empty?
    begin
      return (from_root+path).inject(Object) { |ns,name| ns.const_get(name) }
    rescue NameError
      from_root.delete_at(-1)
    end
  end
  path.inject(Object) { |ns,name| ns.const_get(name) }
end