VimPdb For Linux

VimPdb is a module that provides an integration of the Python debugger pdb into the VIM editor.

Python code

Using vimpdb is easy -- just insert a call to set_trace in your code almost as usual:

import vimpdb; vimpdb.set_trace()

Then start your python application/script.

When the python interpreter hits that line, vimpdb will launch a VIM instance. VIM should get the focus; it loads the source file at the right line.

VIM commands

In VIM, you may now use the following commands:

:PDBNext n pdb (n)ext :PDBStep s pdb (s)tep :PDBArgs a pdb (a)rgs :PDBUp u pdb (u)p :PDBDown d pdb (d)own :PDBReturn r pdb (r)eturn :PDBContinue c pdb (c)ontinue :PDBBreak b Sets a breakpoint at the line on which the cursor is sitting; similar to pdb b(reak) :PDBClear B Clears a breakpoint at the line on which the cursor is sitting; similar to pdb cl(ear) :PDBWord w Evaluates the value of the identifier on which the cursor is sitting. :PDBEval ? Evaluates a Python expression after having asked for it. :PDBReset x Switch back to normal debugging in shell with standard pdb. N/A v(im) Switch back to vimpdb; only in plain pdb.

Standard pdb hook

If you find it hard to change habits and keep on typing

import pdb; pdb.set_trace()

you can add the following line to the .pdbrc file sitting in your home folder:

import vimpdb; vimpdb.hookPdb()

This way, the command v(im) mentioned above is added to your standard pdb and you can switch to vimpdb at any time.

vimpdb has been used successfully under Linux, Mac OSX and Windows.

It is compatible with Python 2.7, 2.6, 2.5 and 2.4. It is not compatible with Python 3.1 (it should be the same for 3.0).

vimpdb requires an installation of VIM that supports both python and clientserver options.

Find out if it is the case by issuing the following command at the VIM prompt:

:version

If the options are supported, you will see +clientserver and +python in the output. In the opposite case, you will see -clientserver or -python.

On Linux and Windows, the default VIM build should already be server-enabled.

On Windows, the python option compiled in VIM depends on a specific Python version. Find out if that specific version is installed and works in VIM by issuing the following command at the VIM prompt:

:python import sys; print sys.version

On Mac OSX, you'll want to use MacVIM. MacVIM also has the python option compiled in by default.

Standard installation with easy_install

easy_install vimpdb

You can obviously also use pip.

If you look inside the package, you will see a VIM script file: vimpdb.vim. Do not move it to VIM configuration directory (like ~/.vim/plugin). vimpdb knows how to make the script available to VIM.

Short story

vimpdb tries to avoid depending on any user configuration. If it cannot detect the right configuration by itself, it will ask a few questions which you should be able to answer easily.

Long story

When launched, vimpdb looks for its RC file : ~/.vimpdbrc. If it does not find it, vimpdb creates that file for you from default values.

vimpdb tries a set of default values that should work. It checks if those default values are appropriate. If the default values do not work, vimpdb asks for other values interactively until it has checked that the values provided actually work.

The default values per OS are listed hereunder.

For Linux:

vim_client_script = vim vim_server_script = gvim server_name = GVIM port = 6666

For MacOSX:

vim_client_script = mvim vim_server_script = mvim server_name = VIM port = 6666

For Windows:

vim_client_script = vim.exe vim_server_script = gvim.exe server_name = VIM port = 6666

See below for details about each option.

You are obviously allowed to create and tune that RC file. Nevertheless, the RC file should hold values for all 4 options. If one of them is missing, vimpdb breaks and complains accordingly.

VIM client script - vim_client_script

To communicate with the VIM instance where debugging happens, vimpdb needs to launch another VIM instance in client mode.

vim_client_script option holds the script used to launch that VIM instance with clientserver support.

On Windows, it should hold vim.exe, not gvim.exe. Do not include quotes in the value to take care of whitespace in the path.

VIM server script - vim_server_script

In case no VIM instance is running, vimpdb launches a VIM instance in server mode.

vim_server_script option holds the script used to launch that VIM instance with clientserver support. As debugging in the VIM instance is written with python, that instance must have python support.

On MacOSX and Linux, vim_server_script and vim_client_script can hold the same value.

On Windows, only the graphical VIM can be used as server, reason for the two separate default values as seen above.

Server Name - server_name

The VIM instance in server mode has a name.

By default, vimpdb speaks to the server named VIM, which is the default servername used by VIM.

If you want vimpdb to use another server name, modify the server_name option. It should hold the name of the VIM server you want to be used for debugging.

You may list the currently running VIM servers using:

$ vim --serverlist VIM

Or, on a Mac:

$ /Applications/MacVim.app/Contents/MacOS/Vim --serverlist VIM

When a VIM instance with clientserver support is running, you can find its name by issuing the following command at the VIM prompt:

:echo v:servername

UDP Port - port

VIM communicates to vimpdb through a UDP socket. By default, the socket is opened on port 6666.

If that socket is not available in your system, you can specify an available port number with the port option.

Before version 0.4.1, vimpdb RC file (~/.vimpdbrc) had a single script option. That option has been turned into the vim_client_script option. The upgrade should be transparent.

Before version 0.4.0, vimpdb was configured through environment variables. If you had a working configuration, upgrade should be transparent. The values of VIMPDB_SERVERNAME and VIMPDB_VIMSCRIPT environment variables are setup in the RC file (~/.vimpdbrc). They are put respectively in server_name and script options.