New documentation for the bdb module. Forward-port from rev. 58112, with a few 3k-specific changes.

Author: birkenfeld

Doc/library/bdb.rst

@@ -0,0 +1,337 @@
+:mod:`bdb` --- Debugger framework
+=================================
+
+.. module:: bdb
+   :synopsis: Debugger framework.
+
+The :mod:`bdb` module handles basic debugger functions, like setting breakpoints
+or managing execution via the debugger.
+
+The following exception is defined:
+
+.. exception:: BdbQuit
+
+   Exception raised by the :class:`Bdb` class for quitting the debugger.
+
+
+The :mod:`bdb` module also defines two classes:
+
+.. class:: Breakpoint(self, file, line[, temporary=0[, cond=None [, funcname=None]]])
+
+   This class implements temporary breakpoints, ignore counts, disabling and
+   (re-)enabling, and conditionals.
+
+   Breakpoints are indexed by number through a list called :attr:`bpbynumber`
+   and by ``(file, line)`` pairs through :attr:`bplist`.  The former points to a
+   single instance of class :class:`Breakpoint`.  The latter points to a list of
+   such instances since there may be more than one breakpoint per line.
+
+   When creating a breakpoint, its associated filename should be in canonical
+   form.  If a *funcname* is defined, a breakpoint hit will be counted when the
+   first line of that function is executed.  A conditional breakpoint always
+   counts a hit.
+
+:class:`Breakpoint` instances have the following methods:
+
+.. method:: Breakpoint.deleteMe()
+
+   Delete the breakpoint from the list associated to a file/line.  If it is the
+   last breakpoint in that position, it also deletes the entry for the
+   file/line.
+
+.. method:: Breakpoint.enable()
+
+   Mark the breakpoint as enabled.
+
+.. method:: Breakpoint.disable()
+
+   Mark the breakpoint as disabled.
+
+.. method:: Breakpoint.bpprint([out])
+
+   Print all the information about the breakpoint:
+
+   * The breakpoint number.
+   * If it is temporary or not.
+   * Its file,line position.
+   * The condition that causes a break.
+   * If it must be ignored the next N times.
+   * The breakpoint hit count.
+
+
+.. class:: Bdb()
+
+   The :class:`Bdb` acts as a generic Python debugger base class.
+
+   This class takes care of the details of the trace facility; a derived class
+   should implement user interaction.  The standard debugger class
+   (:class:`pdb.Pdb`) is an example.
+
+
+The following methods of :class:`Bdb` normally don't need to be overridden.
+
+.. method:: Bdb.canonic(filename)
+
+   Auxiliary method for getting a filename in a canonical form, that is, as a
+   case-normalized (on case-insensitive filesystems) absolute path, stripped
+   of surrounding angle brackets.
+
+.. method:: Bdb.reset()
+
+   Set the :attr:`botframe`, :attr:`stopframe`, :attr:`returnframe` and
+   :attr:`quitting` attributes with values ready to start debugging.
+
+
+.. method:: Bdb.trace_dispatch(frame, event, arg)
+
+   This function is installed as the trace function of debugged frames.  Its
+   return value is the new trace function (in most cases, that is, itself).
+
+   The default implementation decides how to dispatch a frame, depending on the
+   type of event (passed as a string) that is about to be executed.  *event* can
+   be one of the following:
+
+   * ``"line"``: A new line of code is going to be executed.
+   * ``"call"``: A function is about to be called, or another code block
+     entered.
+   * ``"return"``: A function or other code block is about to return.
+   * ``"exception"``: An exception has occurred.
+   * ``"c_call"``: A C function is about to be called.
+   * ``"c_return"``: A C function has returned.
+   * ``"c_exception"``: A C function has thrown an exception.
+
+   For the Python events, specialized functions (see below) are called.  For the
+   C events, no action is taken.
+
+   The *arg* parameter depends on the previous event.
+
+   For more information on trace functions, see :ref:`debugger-hooks`.  For more
+   information on code and frame objects, refer to :ref:`types`.
+
+.. method:: Bdb.dispatch_line(frame)
+
+   If the debugger should stop on the current line, invoke the :meth:`user_line`
+   method (which should be overridden in subclasses).  Raise a :exc:`BdbQuit`
+   exception if the :attr:`Bdb.quitting` flag is set (which can be set from
+   :meth:`user_line`).  Return a reference to the :meth:`trace_dispatch` method
+   for further tracing in that scope.
+
+.. method:: Bdb.dispatch_call(frame, arg)
+
+   If the debugger should stop on this function call, invoke the
+   :meth:`user_call` method (which should be overridden in subclasses).  Raise a
+   :exc:`BdbQuit` exception if the :attr:`Bdb.quitting` flag is set (which can
+   be set from :meth:`user_call`).  Return a reference to the
+   :meth:`trace_dispatch` method for further tracing in that scope.
+
+.. method:: Bdb.dispatch_return(frame, arg)
+
+   If the debugger should stop on this function return, invoke the
+   :meth:`user_return` method (which should be overridden in subclasses).  Raise
+   a :exc:`BdbQuit` exception if the :attr:`Bdb.quitting` flag is set (which can
+   be set from :meth:`user_return`).  Return a reference to the
+   :meth:`trace_dispatch` method for further tracing in that scope.
+
+.. method:: Bdb.dispatch_exception(frame, arg)
+
+   If the debugger should stop at this exception, invokes the
+   :meth:`user_exception` method (which should be overridden in subclasses).
+   Raise a :exc:`BdbQuit` exception if the :attr:`Bdb.quitting` flag is set
+   (which can be set from :meth:`user_exception`).  Return a reference to the
+   :meth:`trace_dispatch` method for further tracing in that scope.
+
+Normally derived classes don't override the following methods, but they may if
+they want to redefine the definition of stopping and breakpoints.
+
+.. method:: Bdb.stop_here(frame)
+
+   This method checks if the *frame* is somewhere below :attr:`botframe` in the
+   call stack.  :attr:`botframe` is the frame in which debugging started.
+
+.. method:: Bdb.break_here(frame)
+
+   This method checks if there is a breakpoint in the filename and line
+   belonging to *frame* or, at least, in the current function.  If the
+   breakpoint is a temporary one, this method deletes it.
+
+.. method:: Bdb.break_anywhere(frame)
+
+   This method checks if there is a breakpoint in the filename of the current
+   frame.
+
+Derived classes should override these methods to gain control over debugger
+operation.
+
+.. method:: Bdb.user_call(frame, argument_list)
+
+   This method is called from :meth:`dispatch_call` when there is the
+   possibility that a break might be necessary anywhere inside the called
+   function.
+
+.. method:: Bdb.user_line(frame)
+
+   This method is called from :meth:`dispatch_line` when either
+   :meth:`stop_here` or :meth:`break_here` yields True.
+
+.. method:: Bdb.user_return(frame, return_value)
+
+   This method is called from :meth:`dispatch_return` when :meth:`stop_here`
+   yields True.
+
+.. method:: Bdb.user_exception(frame, exc_info)
+
+   This method is called from :meth:`dispatch_exception` when :meth:`stop_here`
+   yields True.
+
+.. method:: Bdb.do_clear(arg)
+
+   Handle how a breakpoint must be removed when it is a temporary one.
+
+   This method must be implemented by derived classes.
+
+
+Derived classes and clients can call the following methods to affect the 
+stepping state.
+
+.. method:: Bdb.set_step()
+
+   Stop after one line of code.
+
+.. method:: Bdb.set_next(frame)
+
+   Stop on the next line in or below the given frame.
+
+.. method:: Bdb.set_return(frame)
+
+   Stop when returning from the given frame.
+
+.. method:: Bdb.set_trace([frame])
+
+   Start debugging from *frame*.  If *frame* is not specified, debugging starts
+   from caller's frame.
+
+.. method:: Bdb.set_continue()
+
+   Stop only at breakpoints or when finished.  If there are no breakpoints, set
+   the system trace function to None.
+
+.. method:: Bdb.set_quit()
+
+   Set the :attr:`quitting` attribute to True.  This raises :exc:`BdbQuit` in
+   the next call to one of the :meth:`dispatch_\*` methods.
+
+
+Derived classes and clients can call the following methods to manipulate
+breakpoints.  These methods return a string containing an error message if
+something went wrong, or ``None`` if all is well.
+
+.. method:: Bdb.set_break(filename, lineno[, temporary=0[, cond[, funcname]]])
+
+   Set a new breakpoint.  If the *lineno* line doesn't exist for the *filename*
+   passed as argument, return an error message.  The *filename* should be in
+   canonical form, as described in the :meth:`canonic` method.
+
+.. method:: Bdb.clear_break(filename, lineno)
+
+   Delete the breakpoints in *filename* and *lineno*.  If none were set, an
+   error message is returned.
+
+.. method:: Bdb.clear_bpbynumber(arg)
+
+   Delete the breakpoint which has the index *arg* in the
+   :attr:`Breakpoint.bpbynumber`.  If `arg` is not numeric or out of range,
+   return an error message.
+
+.. method:: Bdb.clear_all_file_breaks(filename)
+
+   Delete all breakpoints in *filename*.  If none were set, an error message is
+   returned.
+
+.. method:: Bdb.clear_all_breaks()
+
+   Delete all existing breakpoints.
+
+.. method:: Bdb.get_break(filename, lineno)
+
+   Check if there is a breakpoint for *lineno* of *filename*.
+
+.. method:: Bdb.get_breaks(filename, lineno)
+
+   Return all breakpoints for *lineno* in *filename*, or an empty list if none
+   are set.
+
+.. method:: Bdb.get_file_breaks(filename)
+
+   Return all breakpoints in *filename*, or an empty list if none are set.
+
+.. method:: Bdb.get_all_breaks()
+
+   Return all breakpoints that are set.
+
+
+Derived classes and clients can call the following methods to get a data
+structure representing a stack trace.
+
+.. method:: Bdb.get_stack(f, t)
+
+   Get a list of records for a frame and all higher (calling) and lower frames,
+   and the size of the higher part.
+
+.. method:: Bdb.format_stack_entry(frame_lineno, [lprefix=': '])
+
+   Return a string with information about a stack entry, identified by a
+   ``(frame, lineno)`` tuple:
+
+   * The canonical form of the filename which contains the frame.
+   * The function name, or ``"<lambda>"``.
+   * The input arguments.
+   * The return value.
+   * The line of code (if it exists).
+
+
+The following two methods can be called by clients to use a debugger to debug a
+statement, given as a string.
+
+.. method:: Bdb.run(cmd, [globals, [locals]])
+
+   Debug a statement executed via the :func:`exec` function.  *globals*
+   defaults to :attr:`__main__.__dict__`, *locals* defaults to *globals*.
+
+.. method:: Bdb.runeval(expr, [globals, [locals]])
+
+   Debug an expression executed via the :func:`eval` function.  *globals* and
+   *locals* have the same meaning as in :meth:`run`.
+
+.. method:: Bdb.runctx(cmd, globals, locals)
+
+   For backwards compatibility.  Calls the :meth:`run` method.
+
+.. method:: Bdb.runcall(func, *args, **kwds)
+
+   Debug a single function call, and return its result.
+
+
+Finally, the module defines the following functions:
+
+.. function:: checkfuncname(b, frame)
+
+   Check whether we should break here, depending on the way the breakpoint *b*
+   was set.
+   
+   If it was set via line number, it checks if ``b.line`` is the same as the one
+   in the frame also passed as argument.  If the breakpoint was set via function
+   name, we have to check we are in the right frame (the right function) and if
+   we are in its first executable line.
+
+.. function:: effective(file, line, frame)
+
+   Determine if there is an effective (active) breakpoint at this line of code.
+   Return breakpoint number or 0 if none.
+	
+   Called only if we know there is a breakpoint at this location.  Returns the
+   breakpoint that was triggered and a flag that indicates if it is ok to delete
+   a temporary breakpoint.
+
+.. function:: set_trace()
+
+   Starts debugging with a :class:`Bdb` instance from caller's frame.

Doc/library/debug.rst

@@ -0,0 +1,17 @@
+***********************
+Debugging and Profiling
+***********************
+
+These libraries help you with Python development: the debugger enables you to
+step through code, analyze stack frames and set breakpoints etc., and the
+profilers run code and give you a detailed breakdown of execution times,
+allowing you to identify bottlenecks in your programs.
+
+.. toctree::
+
+   bdb.rst
+   pdb.rst
+   profile.rst
+   hotshot.rst
+   timeit.rst
+   trace.rst

Doc/library/index.rst

@@ -64,11 +64,7 @@ over 2500 additional components available from the `Python Package Index
    frameworks.rst
    tk.rst
    development.rst
-   pdb.rst
-   profile.rst
-   hotshot.rst
-   timeit.rst
-   trace.rst
+   debug.rst
    python.rst
    custominterp.rst
    modules.rst

Doc/library/pdb.rst

@@ -1,9 +1,8 @@
 
 .. _debugger:
 
-*******************
-The Python Debugger
-*******************
+:mod:`pdb` --- The Python Debugger
+==================================
 
 .. module:: pdb
    :synopsis: The Python debugger for interactive interpreters.