Difference between revisions of "Python"

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     cscope -R  
     cscope -R  
now install the '''xcscope''' emacs package with [[ELPA]]. When done, you can either enable the mode with '''cscope-minor-mode''' (which will add a menu you are free to explore) or call some functions like {{Command|cscope-find-global-definition}}, {{Command|cscope-find-functions-calling-this-function}}, etc.
now install the '''xcscope''' emacs package with [[ELPA]] and require it:
    (require 'xcscope)
When done, you can either enable the mode with '''cscope-minor-mode''' (which will add a menu you are free to explore) or call some functions like {{Command|cscope-find-global-definition}}, {{Command|cscope-find-functions-calling-this-function}}, etc.
= Debugging =
= Debugging =

Revision as of 12:31, 21 January 2014

Default modes

There are a number of python modes for Emacs. fgallina's python.el is the python.el included in Emacs 24.2 and onwards.

All-in-one solutions


emacs-for-python is a bundle of the above modes (and more), and it's an easy way to turn Emacs into a Python IDE.

emacs-for-python at github


Elpy is a collection of elisp packages for Python too.



rope & ropemacs

rope is a library for refactoring and manipulating Python code. ropemacs is an Emacs interface to the rope library.

rope homepage

ropemacs homepage


Jedi.el is a Python auto-completion package for Emacs. It aims at helping your Python coding in a non-destructive way. It also helps you to find information about Python objects, such as docstring, function arguments and code location.

Jedi is simple to install and it just works.

See screenshots and get the full documentation : http://tkf.github.io/emacs-jedi/released/

Jedi's official page: http://jedi.jedidjah.ch/en/latest/


Install Jedi.el via el-get, Marmalade or MELPA (see install for more info) and add this to your Emacs configuration:

   (add-hook 'python-mode-hook 'jedi:setup)
   (setq jedi:setup-keys t)                      ; optional
   (setq jedi:complete-on-dot t)                 ; optional

or call M-x jedi:setup

Code Checker


flymake is a on-the-fly syntax checker for Emacs. We can use it alongside with flyspell.

To run pep8, pylint, pyflakes and unit-tests (with nose), you can be interested in using flymake-python.

Don't forget about pylint too.

Indexing sources: ctags, cscope, pycscope

etags, ctags

Etags (Exuberant Ctags) generates an index (or tag) file of language objects found in source files that allows these items to be quickly and easily located by a text editor or other utility. A tag signifies a language object for which an index entry is available (or, alternatively, the index entry created for that object). Etags is a multilingual implementation of ctags.

The primary use for the tags files is looking up class/method/function/constant/etc declaration/definitions. Cscope is more powerful (see below).


Generate the tags with this command at the root of your project:

    find . -name "*.py" -print | etags -

it creates the file TAGS.

Note that projects like Projectile or Helm provide an integrated use of etags (finding one, re-generating the index, etc).


cscope is a much more powerful beast. While it operates on more or less the same principle (generating a file of useful metadata) it allows you do some fancier things like find all references to a symbol, see where a function is being invoked, etc (you can find definitions as well).

It is originally designed for C and C++, but thanks to version 0.3 of pycscope, pythonista can make use of it.


The following commands should get you running:

   apt-get install cscope
   pip install pycscope
   # in project base dir:
   find . -name '*.py' > cscope.files
   cscope -R 

now install the xcscope emacs package with ELPA and require it:

   (require 'xcscope)

When done, you can either enable the mode with cscope-minor-mode (which will add a menu you are free to explore) or call some functions like M-x cscope-find-global-definition, M-x cscope-find-functions-calling-this-function, etc.


Ipdb, ipython debugger

If you call ipdb, the execution will stop and give a nice ipython-looking prompt. Just add `import ipdb; ipdb.set_trace()`

You can use the following to highlight this line, and not forget it :

; Highlight the call to ipdb
; src http://pedrokroger.com/2010/07/configuring-emacs-as-a-python-ide-2/
(defun annotate-pdb ()
  (highlight-lines-matching-regexp "import ipdb")
  (highlight-lines-matching-regexp "ipdb.set_trace()"))
(add-hook 'python-mode-hook 'annotate-pdb)

pdb track

If you use emacs-for-python given above, you can track your source code while debugging with pdbtrack.

A tool to use in a non-emacs terminal would be pdbpp

Other tools


Pymacs is an Emacs extension that enables the use of Python alongside with Emacs Lisp.

Pymacs homepage

See also

You'll be certainly interested in :

  • Magit, a git interface. Emacs + git is magic : see magit
  • virtualenvwrapper, to load a virtualenv (so than you can use it with M-x compile) (available through ELPA)
  • ELPA packages

If you're running Emacs 24, check out what is available in ELPA:

M-x list-packages  
and see flymake-pyhon-pyflakes, flymake-shell, virtualenv, abl-mode (a python TDD minor-mode), jedi (a python auto-completion for emacs), nose (easy python test-running in emacs), pyregexp, python-magic and more.