utils.py

   1 # This file is part of Realism, which is Copyright FunnyMan3595 (Charlie Nolan)
   2 # and licensed under the GNU GPL v3.  For more details, see LICENSE in the main
   3 # Realism directory.
   4
   5 # This file is dual-licensed under the LGPL.
   6
   7 '''This module holds a few generic utilities that could be of use in many programs.
   8
   9 to_bool(value): converts a string to a boolean semantically, as for a config file.
  10 any, all: Implementations of these standard functions for older versions of Python.'''
  11
  12 def to_bool(value):
  13   '''Converts a string to a boolean semantically.  Usage:
  14      to_bool("tRuE") -> True
  15      to_bool("no") -> False
  16      to_bool("spam") -> raises ValueError
  17
  18      Acceptable values (case insensitive):
  19      True: t, true, y, yes, on, enable, 1
  20      False: f, false, n, no, off, disable, 0'''
  21   false = ['f','false','n','no','off', 'disable', '0']
  22   true = ['t','true','y','yes','on', 'enable', '1']
  23   temp = str(value).strip().lower()
  24   if temp in false:
  25     return False
  26   elif temp in true:
  27     return True
  28   else:
  29     raise ValueError("Cannot parse boolean from input: %s" % value)
  30
  31 # Allows all and any to handle either one iterable object or a set of arguments.
  32 def _arglist(*args):
  33   '''Returns an iterable, either the sole argument passed to it or the entire argument tuple.  Usage:
  34      _arglist(a_list) -> a_list
  35      _arglist(foo, bar, baz) -> (foo, bar, baz)
  36      _arglist("hiya") -> ("hiya",)'''
  37   from types import GeneratorType as generator
  38   if len(args) == 1 and type(args[0]) in (list, tuple, generator):
  39     return args[0]
  40   else:
  41     return args
  42
  43 def all(*args):
  44   '''Legacy implementaiton of Python's all function.  Returns true if all elements are true.  Usage:
  45      all(list_of_true_elements) -> True
  46      all(True, True, True) -> True
  47      all(True, False) -> False
  48      all() -> True'''
  49   AND = lambda a,b: a and b
  50   return reduce(AND, _arglist(*args), True)
  51
  52 def any(*args):
  53   '''Legacy implementation of Python's any function.  Returns true if any element is true.  Usage:
  54      any(list_with_a_true_element) -> True
  55      any(False, True, False) -> True
  56      any(False, False) -> False
  57      any() -> False'''
  58   OR = lambda a,b: a or b
  59   return reduce(OR, _arglist(*args), False)