diff --git a/Doc/library/warnings.rst b/Doc/library/warnings.rst index d121f320d6a..a481a3509d4 100644 --- a/Doc/library/warnings.rst +++ b/Doc/library/warnings.rst @@ -19,10 +19,10 @@ Python programmers issue warnings by calling the :func:`warn` function defined in this module. (C programmers use :c:func:`PyErr_WarnEx`; see :ref:`exceptionhandling` for details). -Warning messages are normally written to ``sys.stderr``, but their disposition +Warning messages are normally written to :data:`sys.stderr`, but their disposition can be changed flexibly, from ignoring all warnings to turning them into -exceptions. The disposition of warnings can vary based on the warning category -(see below), the text of the warning message, and the source location where it +exceptions. The disposition of warnings can vary based on the :ref:`warning category +`, the text of the warning message, and the source location where it is issued. Repetitions of a particular warning for the same source location are typically suppressed. @@ -31,7 +31,7 @@ determination is made whether a message should be issued or not; next, if a message is to be issued, it is formatted and printed using a user-settable hook. The determination whether to issue a warning message is controlled by the -warning filter, which is a sequence of matching rules and actions. Rules can be +:ref:`warning filter `, which is a sequence of matching rules and actions. Rules can be added to the filter by calling :func:`filterwarnings` and reset to its default state by calling :func:`resetwarnings`. @@ -181,9 +181,9 @@ Describing Warning Filters The warnings filter is initialized by :option:`-W` options passed to the Python interpreter command line and the :envvar:`PYTHONWARNINGS` environment variable. The interpreter saves the arguments for all supplied entries without -interpretation in ``sys.warnoptions``; the :mod:`warnings` module parses these +interpretation in :data:`sys.warnoptions`; the :mod:`warnings` module parses these when it is first imported (invalid options are ignored, after printing a -message to ``sys.stderr``). +message to :data:`sys.stderr`). Individual warnings filters are specified as a sequence of fields separated by colons:: @@ -192,7 +192,7 @@ colons:: The meaning of each of these fields is as described in :ref:`warning-filter`. When listing multiple filters on a single line (as for -:envvar:`PYTHONWARNINGS`), the individual filters are separated by commas,and +:envvar:`PYTHONWARNINGS`), the individual filters are separated by commas and the filters listed later take precedence over those listed before them (as they're applied left-to-right, and the most recently applied filters take precedence over earlier ones). @@ -395,12 +395,12 @@ Available Functions .. function:: warn(message, category=None, stacklevel=1, source=None) Issue a warning, or maybe ignore it or raise an exception. The *category* - argument, if given, must be a warning category class (see above); it defaults to - :exc:`UserWarning`. Alternatively *message* can be a :exc:`Warning` instance, + argument, if given, must be a :ref:`warning category class `; it + defaults to :exc:`UserWarning`. Alternatively, *message* can be a :exc:`Warning` instance, in which case *category* will be ignored and ``message.__class__`` will be used. - In this case the message text will be ``str(message)``. This function raises an + In this case, the message text will be ``str(message)``. This function raises an exception if the particular warning issued is changed into an error by the - warnings filter see above. The *stacklevel* argument can be used by wrapper + :ref:`warnings filter `. The *stacklevel* argument can be used by wrapper functions written in Python, like this:: def deprecation(message): @@ -444,7 +444,7 @@ Available Functions Write a warning to a file. The default implementation calls ``formatwarning(message, category, filename, lineno, line)`` and writes the - resulting string to *file*, which defaults to ``sys.stderr``. You may replace + resulting string to *file*, which defaults to :data:`sys.stderr`. You may replace this function with any callable by assigning to ``warnings.showwarning``. *line* is a line of source code to be included in the warning message; if *line* is not supplied, :func:`showwarning` will