Pyclewn allows using vim as a front end to a debugger. Pyclewn currently supports gdb and pdb.

The debugger output is redirected to a vim window, the pyclewn console. The debugger commands are mapped to vim user-defined commands with a common letter prefix, and with completion available on the commands and their first argument.

On unix when running gvim, the controlling terminal of the program to debug is the terminal used to launch pyclewn. Any other terminal can be used when the debugger allows it, for example after using the attach or tty gdb commands or using the --tty option with pdb. On Windows, gdb pops up a console attached to the program to debug.

Features

• A debugger command can be mapped in vim to a key sequence using vim key mappings. This allows, for example, to set/clear a breakpoint or print a variable value at the current cursor or mouse position by just hitting a key.
• A sequence of gdb commands can be run from a vim script when the async option is set. This may be useful in a key mapping.
• Breakpoints and the line in the current frame, are highlighted in the source code. Disabled breakpoints are noted with a different highlighting color. Pyclewn automatically finds the source file for the breakpoint if it exists, and tells vim to load and display the file and highlight the line.
• Multiple consecutive pyclewn sessions can be started from within vim with the :Pyclewn command.
• The value of an expression or variable is displayed in a balloon in gvim when the mouse pointer is hovering over the selected expression or the variable.
• Similarly to gdb, one may attach to a running python process with the pdb debugger, interrupt the process, manage a debugging session and terminate the debugging session by detaching from the process. A new debugging session may be conducted later on this same process, possibly from another Vim instance.
• An expression can be watched in a vim window. The expression value is updated and highlighted whenever it has changed. When the expression is a structure or class instance, it can be expanded (resp. folded) to show (resp. hide) its members and their values. This feature is only available with gdb.
• The project command saves the current gdb settings to a project file that may be sourced later by the gdb source command. These settings are the working directory, the debuggee program file name, the program arguments and the breakpoints. The sourcing and saving of the project file can be automated to occur on each gdb startup and termination, whith the project command line option. The project command is currently only available with gdb.
• Vim command completion on the commands and their first argument.

Note

Pyclewn uses the netbeans protocol to interact with vim. Vim implementation of netbeans in plain vim (vim running in a terminal) is available since vim version 7.3.

The vim :nbstart command that allows pyclewn to be started from within vim, is available since vim version 7.3.

Support of Python 3 is available since pyclewn 1.6.

Comparison of clewn, vimGdb and pyclewn

The following table lists the differences between clewn, vimGdb and pyclewn.

	vimGdb	clewn	pyclewn
platform	unix	unix	all unix platforms supported by python - requires GNU gdb from macports on Mac Os X Windows (Python 3 only)
language	C	C	Python 2.4 and above Python 3
vim mode	vim in a terminal, gvim	gvim	vim in a terminal (vim 7.3 or above required), gvim
vim interface	a vim patch	a standalone program connected to gvim with a netbeans socket	a standalone program connected to vim with a netbeans socket pyclewn may be started from within vim
vim version	a different patch for each vim version	vim 6.3 and above	vim 7.0 and above
debuggers	gdb	gdb	gdb, pdb
gdb features		watched variables project file	tight integration with vim gdb/mi interface asynchronous gdb commands watched variables project file
pdb features			interrupt the debuggee attach to a running python process the threadstack command