FILE, DIR

inspired by: PHP __DIR__, __FILE__ [1]
status:
  python34: __file__ is absolute [2]
  discussion: [3], status: Sep 28 18:51:29 CEST 2013

variants:
 - name: with import (27,33 compatible)
   set:
    - from os.path import FILE, DIR
    - from hacks import FILE, DIR
    - from future import FILE, DIR

 - name: auto global (28,35)
   set:
    - FILE, DIR
    - __file__, __dir__
    - __abs_file__, __abs_dir__ (MRAB, Philipp A.)

1. http://www.php.net/manual/en/language.constants.predefined.php

2. https://docs.python.org/3.5/whatsnew/3.4.html

objections:
 - new globals are bad (Cameron Simpson)
 - names starting with __ are bad (Cameron Simpson)
 - retrieving abs dir is trivial code (Cameron Simpson)
 - abspath is not always possible (Cameron Simpson)
 - there should not be convenience functions (Cameron Simpson)