# MIT License
#
# Copyright The SCons Foundation
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"""Option type for true/false Variables.
Usage example::
opts = Variables()
opts.Add(BoolVariable('embedded', 'build for an embedded system', 0))
...
if env['embedded'] == 1:
...
"""
__all__ = ['BoolVariable',]
import SCons.Errors
__true_strings = ('y', 'yes', 'true', 't', '1', 'on' , 'all' )
__false_strings = ('n', 'no', 'false', 'f', '0', 'off', 'none')
[docs]def _text2bool(val):
"""
Converts strings to True/False depending on the 'truth' expressed by
the string. If the string can't be converted, the original value
will be returned.
See '__true_strings' and '__false_strings' for values considered
'true' or 'false respectively.
This is usable as 'converter' for SCons' Variables.
"""
lval = val.lower()
if lval in __true_strings: return True
if lval in __false_strings: return False
raise ValueError("Invalid value for boolean option: %s" % val)
[docs]def _validator(key, val, env):
"""
Validates the given value to be either '0' or '1'.
This is usable as 'validator' for SCons' Variables.
"""
if not env[key] in (True, False):
raise SCons.Errors.UserError(
'Invalid value for boolean option %s: %s' % (key, env[key]))
[docs]def BoolVariable(key, help, default):
"""
The input parameters describe a boolean option, thus they are
returned with the correct converter and validator appended. The
'help' text will by appended by '(yes|no) to show the valid
valued. The result is usable for input to opts.Add().
"""
return (key, '%s (yes|no)' % help, default,
_validator, _text2bool)
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