1 #!/usr/bin/env python 2 3 """ 4 Identity-related functions. 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 from native import isinstance as _isinstance, issubclass as _issubclass 23 24 def callable(obj): 25 26 "Return whether 'obj' is callable." 27 28 # NOTE: Classes and functions are callable, modules are not callable, 29 # NOTE: only instances with __call__ methods should be callable. 30 31 pass 32 33 def id(obj): 34 35 # NOTE: This should show an object's address, but it is currently 36 # NOTE: unsupported. 37 38 pass 39 40 def isclass(obj): 41 42 "Return whether 'obj' is a class." 43 44 return obj.__class__ is type 45 46 def isinstance(obj, cls_or_tuple): 47 48 """ 49 Return whether 'obj' is an instance of 'cls_or_tuple', where the latter is 50 either a class or a sequence of classes. 51 """ 52 53 if _isinstance(cls_or_tuple, tuple): 54 for cls in cls_or_tuple: 55 if obj.__class__ is cls or isclass(cls) and _isinstance(obj, cls): 56 return True 57 return False 58 else: 59 return obj.__class__ is cls_or_tuple or isclass(cls_or_tuple) and _isinstance(obj, cls_or_tuple) 60 61 def issubclass(obj, cls_or_tuple): 62 63 """ 64 Return whether 'obj' is a class that is a subclass of 'cls_or_tuple', where 65 the latter is either a class or a sequence of classes. If 'obj' is the same 66 as the given class or classes, True is also returned. 67 """ 68 69 if not isclass(obj): 70 return False 71 elif _isinstance(cls_or_tuple, tuple): 72 for cls in cls_or_tuple: 73 if obj is cls or isclass(cls) and _issubclass(obj, cls): 74 return True 75 return False 76 else: 77 return obj is cls_or_tuple or isclass(cls_or_tuple) and _issubclass(obj, cls_or_tuple) 78 79 def repr(obj): 80 81 "Return a program representation for 'obj'." 82 83 # Class attributes of instances provide __repr__. 84 85 return obj.__repr__() 86 87 # vim: tabstop=4 expandtab shiftwidth=4
