Source Code for Module SCons.Variables.BoolVariable'

 1  """engine.SCons.Variables.BoolVariable 
 2   
 3  This file defines the option type for SCons implementing true/false values. 
 4   
 5  Usage example: 
 6   
 7    opts = Variables() 
 8    opts.Add(BoolVariable('embedded', 'build for an embedded system', 0)) 
 9    ... 
10    if env['embedded'] == 1: 
11      ... 
12  """ 
13   
14  # 
15  # Copyright (c) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010 The SCons Foundation 
16  # 
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18  # a copy of this software and associated documentation files (the 
19  # "Software"), to deal in the Software without restriction, including 
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24  # 
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29  # KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE 
30  # WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND 
31  # NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE 
32  # LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION 
33  # OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION 
34  # WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. 
35  # 
36   
37  __revision__ = "src/engine/SCons/Variables/BoolVariable.py 5110 2010/07/25 16:14:38 bdeegan" 
38   
39  __all__ = ['BoolVariable',] 
40   
41  import string 
42   
43  import SCons.Errors 
44   
45  __true_strings  = ('y', 'yes', 'true', 't', '1', 'on' , 'all' ) 
46  __false_strings = ('n', 'no', 'false', 'f', '0', 'off', 'none') 
47   
48   
49 -def _text2bool(val): 
50      """ 
51      Converts strings to True/False depending on the 'truth' expressed by 
52      the string. If the string can't be converted, the original value 
53      will be returned. 
54   
55      See '__true_strings' and '__false_strings' for values considered 
56      'true' or 'false respectivly. 
57   
58      This is usable as 'converter' for SCons' Variables. 
59      """ 
60      lval = string.lower(val) 
61      if lval in __true_strings: return True 
62      if lval in __false_strings: return False 
63      raise ValueError("Invalid value for boolean option: %s" % val) 
64   
65   
66 -def _validator(key, val, env): 
67      """ 
68      Validates the given value to be either '0' or '1'. 
69       
70      This is usable as 'validator' for SCons' Variables. 
71      """ 
72      if not env[key] in (True, False): 
73          raise SCons.Errors.UserError( 
74              'Invalid value for boolean option %s: %s' % (key, env[key])) 
75   
76   
77 -def BoolVariable(key, help, default): 
78      """ 
79      The input parameters describe a boolen option, thus they are 
80      returned with the correct converter and validator appended. The 
81      'help' text will by appended by '(yes|no) to show the valid 
82      valued. The result is usable for input to opts.Add(). 
83      """ 
84      return (key, '%s (yes|no)' % help, default, 
85              _validator, _text2bool) 
86   
87  # Local Variables: 
88  # tab-width:4 
89  # indent-tabs-mode:nil 
90  # End: 
91  # vim: set expandtab tabstop=4 shiftwidth=4: 
92