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(This doesn't need to be merged to Py3k.)

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+: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 :keyword:`exec` statement.  *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.