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Diffstat (limited to 'Doc/library/constants.rst')
| -rw-r--r-- | Doc/library/constants.rst | 16 |
1 files changed, 9 insertions, 7 deletions
diff --git a/Doc/library/constants.rst b/Doc/library/constants.rst index 0d44b7b..3870874 100644 --- a/Doc/library/constants.rst +++ b/Doc/library/constants.rst @@ -15,19 +15,21 @@ A small number of constants live in the built-in namespace. They are: .. data:: False - The false value of the :class:`bool` type. + The false value of the :class:`bool` type. Assignments to ``False`` + are illegal and raise a :exc:`SyntaxError`. .. data:: True - The true value of the :class:`bool` type. + The true value of the :class:`bool` type. Assignments to ``True`` + are illegal and raise a :exc:`SyntaxError`. .. data:: None The sole value of :attr:`types.NoneType`. ``None`` is frequently used to represent the absence of a value, as when default arguments are not passed to a - function. + function. Assignments to ``None`` are illegal and raise a :exc:`SyntaxError`. .. data:: NotImplemented @@ -42,11 +44,11 @@ A small number of constants live in the built-in namespace. They are: The same as ``...``. Special value used mostly in conjunction with extended slicing syntax for user-defined container data types, as in :: - val = container[1:5, 7:10, ...] + .. XXX Someone who understands extended slicing should fill in here. .. data:: __debug__ - A boolean value that is :data:`True` if Python was not started with the - ``-O`` command line option. Its value is used indirectly by the - :keyword:`assert` statement, but it can also be used directly in code. + This constant is true if Python was not started with an :option:`-O` option. + Assignments to :const:`__debug__` are illegal and raise a :exc:`SyntaxError`. + See also the :keyword:`assert` statement. |