Issue 9264: Document trace module command line options. Patch by Eli Bendersky.

Doc/library/trace.rst

-
 :mod:`trace` --- Trace or track Python statement execution
 ==========================================================
 
@@ -20,59 +19,100 @@ Command Line Usage
 The :mod:`trace` module can be invoked from the command line.  It can be as
 simple as ::
 
-   python -m trace --count somefile.py ...
+   python -m trace --count -C . somefile.py ...
+
+The above will execute :file:`somefile.py` and generate annotated listings of all
+Python modules imported during the execution into the current directory.
+
+Meta-options
+^^^^^^^^^^^^
+
+``--help``
+
+   Display usage and exit.
+
+``--version``
+
+   Display the version of the module and exit.
+
+Main options
+^^^^^^^^^^^^
+
+The ``--listfuncs`` option is mutually exclusive with the ``--trace`` and
+``--count`` options . When ``--listfuncs`` is provided, neither ``--counts``
+nor ``--trace`` are accepted, and vice versa.
+
+``--count, -c``
 
-The above will generate annotated listings of all Python modules imported during
-the execution of :file:`somefile.py`.
+   Produce a set of annotated listing files upon program completion that shows
+   how many times each statement was executed.
+   See also ``--coverdir``, ``--file``, ``--no-report`` below.
 
-The following command-line arguments are supported:
+``--trace, -t``
 
-:option:`--trace`, :option:`-t`
    Display lines as they are executed.
 
-:option:`--count`, :option:`-c`
-   Produce a set of  annotated listing files upon program completion that shows how
-   many times each statement was executed.
+``--listfuncs, -l``
 
-:option:`--report`, :option:`-r`
-   Produce an annotated list from an earlier program run that used the
-   :option:`--count` and :option:`--file` arguments.
+   Display the functions executed by running the program.
 
-:option:`--no-report`, :option:`-R`
-   Do not generate annotated listings.  This is useful if you intend to make
-   several runs with :option:`--count` then produce a single set of annotated
-   listings at the end.
+``--report, -r``
+
+   Produce an annotated list from an earlier program run that used the ``--count``
+   and ``--file`` option. Do not execute any code.
+
+``--trackcalls, -T``
+
+   Display the calling relationships exposed by running the program.
 
-:option:`--listfuncs`, :option:`-l`
-   List the functions executed by running the program.
+Modifiers
+^^^^^^^^^
 
-:option:`--trackcalls`, :option:`-T`
-   Generate calling relationships exposed by running the program.
+``--file=<file>, -f``
 
-:option:`--file`, :option:`-f`
-   Name a file containing (or to contain) counts.
+   Name of a file to accumulate counts over several tracing runs. Should be used
+   with the ``--count`` option.
 
-:option:`--coverdir`, :option:`-C`
-   Name a directory in which to save annotated listing files.
+``--coverdir=<dir>, -C``
+
+   Directory where the report files go. The coverage report for
+   ``package.module`` is written to file ``dir/package/module.cover``.
+
+``--missing, -m``
 
-:option:`--missing`, :option:`-m`
    When generating annotated listings, mark lines which were not executed with
    '``>>>>>>``'.
 
-:option:`--summary`, :option:`-s`
-   When using :option:`--count` or :option:`--report`, write a brief summary to
+``--summary, -s``
+
+   When using ``--count`` or ``--report``, write a brief summary to
    stdout for each file processed.
 
-:option:`--ignore-module`
+``--no-report, -R``
+
+   Do not generate annotated listings.  This is useful if you intend to make
+   several runs with ``--count`` then produce a single set of annotated
+   listings at the end.
+
+``--timing, -g``
+
+   Prefix each line with the time since the program started. Only used while
+   tracing.
+
+Filters
+^^^^^^^
+
+These options may be repeated multiple times.
+
+``--ignore-module=<mod>``
+
    Accepts comma separated list of module names. Ignore each of the named
-   module and its submodules (if it is a package).  May be given
-   multiple times.
+   modules and its submodules (if it is a package).
 
-:option:`--ignore-dir`
-   Ignore all modules and packages in the named directory and subdirectories
-   (multiple directories can be joined by os.pathsep).  May be given multiple
-   times.
+``--ignore-dir=<dir>``
 
+   Ignore all modules and packages in the named directory and subdirectories
+   (multiple directories can be joined by ``os.pathsep``).
 
 .. _trace-api:
 
@@ -80,7 +120,7 @@ Programming Interface
 ---------------------
 
 
-.. class:: Trace([count=1[, trace=1[, countfuncs=0[, countcallers=0[, ignoremods=()[, ignoredirs=()[, infile=None[, outfile=None[, timing=False]]]]]]]]])
+.. class:: Trace(count=1, trace=1, countfuncs=0, countcallers=0, ignoremods=(), ignoredirs=(), infile=None, outfile=None, timing=False)
 
    Create an object to trace execution of a single statement or expression. All
    parameters are optional.  *count* enables counting of line numbers. *trace*
@@ -88,19 +128,20 @@ Programming Interface
    called during the run.  *countcallers* enables call relationship tracking.
    *ignoremods* is a list of modules or packages to ignore.  *ignoredirs* is a list
    of directories whose modules or packages should be ignored.  *infile* is the
-   file from which to read stored count information.  *outfile* is a file in which
-   to write updated count information. *timing* enables a timestamp relative
-   to when tracing was started to be displayed.
+   name of the file from which to read stored count information.  *outfile* is
+   the name of the file in which to write updated count information. *timing*
+   enables a timestamp relative to when tracing was started to be displayed.
 
 
 .. method:: Trace.run(cmd)
 
-   Run *cmd* under control of the Trace object with the current tracing parameters.
+   Run *cmd* under control of the :class:`Trace` object with the current tracing parameters.
+   *cmd* must be a string or code object, suitable for passing into :func:`exec`.
 
 
-.. method:: Trace.runctx(cmd[, globals=None[, locals=None]])
+.. method:: Trace.runctx(cmd, globals=None, locals=None)
 
-   Run *cmd* under control of the Trace object with the current tracing parameters
+   Run *cmd* under control of the :class:`Trace` object with the current tracing parameters
    in the defined global and local environments.  If not defined, *globals* and
    *locals* default to empty dictionaries.
 
@@ -110,7 +151,31 @@ Programming Interface
    Call *func* with the given arguments under control of the :class:`Trace` object
    with the current tracing parameters.
 
-This is a simple example showing the use of this module::
+.. method:: Trace.results()
+
+   Return a :class:`CoverageResults` object that contains the cumulative results
+   of all previous calls to ``run``, ``runctx`` and ``runfunc`` for the given
+   :class:`Trace` instance. Does not reset the accumulated trace results.
+
+.. class:: CoverageResults
+
+   A container for coverage results, created by :meth:`Trace.results`. Should not
+   be created directly by the user.
+
+.. method:: CoverageResults.update(other)
+
+   Merge in data from another :class:`CoverageResults` object.
+
+.. method:: CoverageResults.write_results(show_missing=True, summary=False, coverdir=None)
+
+   Write coverage results. Set *show_missing* to show lines that had no hits.
+   Set *summary* to include in the output the coverage summary per module. *coverdir*
+   specifies the directory into which the coverage result files will be output.
+   If ``None``, the results for each source file are placed in its directory.
+
+..
+
+A simple example demonstrating the use of the programming interface::
 
    import sys
    import trace