# Module: `core.debugger`

Pdb debugger class.

Modified from the standard pdb.Pdb class to avoid including readline, so that the command line completion of other programs which include this isn’t damaged.

In the future, this class will be expanded with improvements over the standard pdb.

The code in this file is mainly lifted out of cmd.py in Python 2.2, with minor changes. Licensing should therefore be under the standard Python terms. For details on the PSF (Python Software Foundation) standard license, see:

https://docs.python.org/2/license.html

## 2 Classes

class `IPython.core.debugger.``Tracer`(colors=None)

  Bases: `object`

  DEPRECATED

  Class for local debugging, similar to pdb.set_trace.

  Instances of this class, when called, behave like pdb.set_trace, but providing IPython’s enhanced capabilities.

  This is implemented as a class which must be initialized in your own code and not as a standalone function because we need to detect at runtime whether IPython is already active or not. That detection is done in the constructor, ensuring that this code plays nicely with a running IPython, while functioning acceptably (though with limitations) if outside of it.

  `__init__`(colors=None)

    DEPRECATED

    Create a local debugger instance.

    Parameters: | colors (str, optional) – The name of the color scheme to use, it must be one of IPython’s valid color schemes. If not given, the function will default to the current IPython scheme when running inside IPython, and to ‘NoColor’ otherwise.

    Examples

        from IPython.core.debugger import Tracer; debug_here = Tracer()

    Later in your code:

        debug_here()  # -> will open up the debugger at that point.

    Once the debugger activates, you can use all of its regular commands to step through code, set breakpoints, etc. See the pdb documentation from the Python standard library for usage details.

class `IPython.core.debugger.``Pdb`(color_scheme=None, completekey=None, stdin=None, stdout=None, context=5)

  Bases: `pdb.Pdb`

  Modified Pdb class, does not load readline.

  for a standalone version that uses prompt_toolkit, see `IPython.terminal.debugger.TerminalPdb` and `IPython.terminal.debugger.set_trace()`

  `__init__`(color_scheme=None, completekey=None, stdin=None, stdout=None, context=5)
  `do_d`(*args, **kw)

    d(own) [count] Move the current frame count (default one) levels down in the stack trace (to a newer frame).

  `do_down`(*args, **kw)

    d(own) [count] Move the current frame count (default one) levels down in the stack trace (to a newer frame).

  `do_pdef`(arg)

    Print the call signature for any callable object.

    The debugger interface to %pdef

  `do_pdoc`(arg)

    Print the docstring for an object.

    The debugger interface to %pdoc.

  `do_pfile`(arg)

    Print (or run through pager) the file where an object is defined.

    The debugger interface to %pfile.

  `do_pinfo`(arg)

    Provide detailed information about an object.

    The debugger interface to %pinfo, i.e., obj?.

  `do_pinfo2`(arg)

    Provide extra detailed information about an object.

    The debugger interface to %pinfo2, i.e., obj??.

  `do_psource`(arg)

    Print (or run through pager) the source code for an object.

  `do_q`(*args, **kw)

    q(uit) exit

    > Quit from the debugger. The program being executed is aborted.

  `do_quit`(*args, **kw)

    q(uit) exit

    > Quit from the debugger. The program being executed is aborted.

  `do_u`(*args, **kw)

    u(p) [count] Move the current frame count (default one) levels up in the stack trace (to an older frame).

  `do_up`(*args, **kw)

    u(p) [count] Move the current frame count (default one) levels up in the stack trace (to an older frame).

  `do_w`(arg)

    w(here) Print a stack trace, with the most recent frame at the bottom. An arrow indicates the “current frame”, which determines the context of most commands. ‘bt’ is an alias for this command.

    Take a number as argument as an (optional) number of context line to print

  `do_where`(arg)

    w(here) Print a stack trace, with the most recent frame at the bottom. An arrow indicates the “current frame”, which determines the context of most commands. ‘bt’ is an alias for this command.

    Take a number as argument as an (optional) number of context line to print

  `new_do_restart`(arg)

    Restart command. In the context of ipython this is exactly the same thing as ‘quit’.

  `print_list_lines`(filename, first, last)

    The printing (as opposed to the parsing part of a ‘list’ command.

  `set_colors`(scheme)

    Shorthand access to the color table scheme selector method.

## 5 Functions

`IPython.core.debugger.``make_arrow`(pad)

  generate the leading arrow in front of traceback or debugger

`IPython.core.debugger.``BdbQuit_excepthook`(et, ev, tb, excepthook=None)

  Exception hook which handles `BdbQuit` exceptions.

  All other exceptions are processed using the `excepthook` parameter.

`IPython.core.debugger.``BdbQuit_IPython_excepthook`(self, et, ev, tb, tb_offset=None)

`IPython.core.debugger.``decorate_fn_with_doc`(new_fn, old_fn, additional_text='')

  Make new_fn have old_fn’s doc string. This is particularly useful for the `do_...` commands that hook into the help system. Adapted from from a comp.lang.python posting by Duncan Booth.

`IPython.core.debugger.``set_trace`(frame=None)

  Start debugging from `frame`.

  If frame is not specified, debugging starts from caller’s frame.