Merged revisions 2725-2865 via svnmerge from

[scons.git] / src / engine / SCons / Variables / BoolVariable.py

diff --git a/src/engine/SCons/Variables/BoolVariable.py b/src/engine/SCons/Variables/BoolVariable.py
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+++ b/src/engine/SCons/Variables/BoolVariable.py
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+"""engine.SCons.Variables.BoolVariable
+
+This file defines the option type for SCons implementing true/false values.
+
+Usage example:
+
+  opts = Variables()
+  opts.Add(BoolVariable('embedded', 'build for an embedded system', 0))
+  ...
+  if env['embedded'] == 1:
+    ...
+"""
+
+#
+# __COPYRIGHT__
+#
+# Permission is hereby granted, free of charge, to any person obtaining
+# a copy of this software and associated documentation files (the
+# "Software"), to deal in the Software without restriction, including
+# without limitation the rights to use, copy, modify, merge, publish,
+# distribute, sublicense, and/or sell copies of the Software, and to
+# permit persons to whom the Software is furnished to do so, subject to
+# the following conditions:
+#
+# The above copyright notice and this permission notice shall be included
+# in all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY
+# KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
+# WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+# LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+# OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+# WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+#
+
+__revision__ = "__FILE__ __REVISION__ __DATE__ __DEVELOPER__"
+
+__all__ = ['BoolVariable',]
+
+import string
+
+import SCons.compat
+import SCons.Errors
+
+__true_strings  = ('y', 'yes', 'true', 't', '1', 'on' , 'all' )
+__false_strings = ('n', 'no', 'false', 'f', '0', 'off', 'none')
+
+
+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 respectivly.
+
+    This is usable as 'converter' for SCons' Variables.
+    """
+    lval = string.lower(val)
+    if lval in __true_strings: return True
+    if lval in __false_strings: return False
+    raise ValueError("Invalid value for boolean option: %s" % val)
+
+
+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]))
+
+
+def BoolVariable(key, help, default):
+    """
+    The input parameters describe a boolen 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)