Source code for SCons.Variables.BoolVariable

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"""Variable type for true/false Variables.

Usage example::

    opts = Variables()
    opts.Add(BoolVariable('embedded', 'build for an embedded system', 0))
    ...
    if env['embedded'] == 1:
    ...
"""

from typing import Tuple, Callable

import SCons.Errors

__all__ = ['BoolVariable',]

TRUE_STRINGS = ('y', 'yes', 'true', 't', '1', 'on' , 'all')
FALSE_STRINGS = ('n', 'no', 'false', 'f', '0', 'off', 'none')


[docs]def _text2bool(val) -> bool: """Converts strings to True/False. If *val* looks like it expresses a bool-like value, based on the :data:`TRUE_STRINGS` and :data:`FALSE_STRINGS` tuples, return the appropriate value. This is usable as a converter function for SCons Variables. Raises: ValueError: if the string cannot be converted. """ 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) -> None: """Validates the given value to be either true or false. This is usable as a validator function for SCons Variables. Raises: KeyError: if key is not set in env UserError: if key does not validate. """ 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) -> Tuple[str, str, str, Callable, Callable]: """Return a tuple describing a boolean SCons Variable. The input parameters describe a boolean option. Returns a tuple including the correct converter and validator. The *help* text will have ``(yes|no)`` automatically appended to show the valid values. The result is usable as input to :meth:`Add`. """ help = '%s (yes|no)' % help return (key, help, default, _validator, _text2bool)
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