1 #!/usr/bin/env python 2 3 """ 4 Tuple 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 from __builtins__.iterator import listiterator 23 from __builtins__.sequence import sequence 24 import native 25 26 class tuple(sequence): 27 28 "Implementation of tuple." 29 30 def __init__(self, args=None): 31 32 "Initialise the tuple." 33 34 # Reserve an attribute for a fragment reference along with some space 35 # for elements. 36 37 size = args is not None and len(args) or 0 38 self.__data__ = native._list_init(size) 39 native._list_setsize(self, size) 40 41 # Populate the tuple. 42 43 if args is not None: 44 i = 0 45 for arg in args: 46 native._list_setelement(self, i, arg) 47 i += 1 48 49 def __getslice__(self, start, end=None): 50 51 "Return a slice starting from 'start', with the optional 'end'." 52 53 return tuple(get_using(sequence.__getslice__, self)(start, end)) 54 55 def __len__(self): 56 57 "Return the length of the tuple." 58 59 return native._list_len(self) 60 61 def __add__(self, other): pass 62 63 def __str__(self): 64 65 "Return a string representation." 66 67 return self._str("(", ")") 68 69 __repr__ = __str__ 70 71 def __bool__(self): 72 73 "Tuples are true if non-empty." 74 75 return self.__len__() != 0 76 77 def __iter__(self): 78 79 "Return an iterator." 80 81 return listiterator(self) 82 83 # Special implementation methods. 84 85 def __get_single_item__(self, index): 86 87 "Return the item at the normalised (positive) 'index'." 88 89 if index >= len(self): 90 raise IndexError(index) 91 92 return native._list_element(self, index) 93 94 def __set_single_item__(self, index, value): 95 96 "Set at the normalised (positive) 'index' the given 'value'." 97 98 raise TypeError(self) 99 100 # vim: tabstop=4 expandtab shiftwidth=4