1 #!/usr/bin/env python 2 3 """ 4 Boolean objects. 5 6 Copyright (C) 2015, 2016 Paul Boddie <paul@boddie.org.uk> 7 8 This program is free software; you can redistribute it and/or modify it under 9 the terms of the GNU General Public License as published by the Free Software 10 Foundation; either version 3 of the License, or (at your option) any later 11 version. 12 13 This program is distributed in the hope that it will be useful, but WITHOUT 14 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS 15 FOR A PARTICULAR PURPOSE. See the GNU General Public License for more 16 details. 17 18 You should have received a copy of the GNU General Public License along with 19 this program. If not, see <http://www.gnu.org/licenses/>. 20 """ 21 22 class boolean: 23 24 "The type of the True and False objects." 25 26 def __bool__(self): 27 28 "Identity operation." 29 30 return self 31 32 def __str__(self): 33 34 "Return a string representation." 35 36 return self is True and "True" or "False" 37 38 __repr__ = __str__ 39 40 False = boolean() 41 True = boolean() 42 43 def bool(obj): 44 45 "Evaluate 'obj' as a boolean value." 46 47 return obj.__bool__() 48 49 # vim: tabstop=4 expandtab shiftwidth=4