Python layer

• Auto-completion using anaconda-mode
• Code Navigation using anaconda-mode
• Documentation Lookup using anaconda-mode and pylookup
• Test Runners using nose.el or pytest
• Virtual Environment using pyvenv and pyenv
• semantic mode is enabled
• PEP8 compliant formatting via YAPF
• PEP8 checks with flake8 or pylint
• Suppression of unused import with autoflake
• Use the % key to jump between blocks with evil-matchit
• Sort imports with isort

To use this configuration layer, add it to your ~/.spacemacs. You will need to add python to the existing dotspacemacs-configuration-layers list in this file.

Both nose and pytest are supported. By default nose is used. To choose your test runner set the layer variable python-test-runner to either nose or pytest.

(setq-default dotspacemacs-configuration-layers
  '((python :variables python-test-runner 'pytest)))

If you need both then you can set python-test-runner to a list like this:

(setq-default dotspacemacs-configuration-layers
  '((python :variables python-test-runner '(pytest nose))))

This means that pytest is your primary test runner. To use the secondary test runner you can call the test functions with a prefix argument e.g. SPC u SPC m t t to run one test with nose.

To set project specific test runners you can set python-test-runner in a directory local variable in your project root. SPC f v d in Spacemacs. See the official documentation for more information.

The root of the project is detected with a .git directory or a setup.cfg file.

anaconda-mode tries to install the dependencies itself but sometimes it does not work and you may encounter the following message when opening a python buffer:

Blocking call to accept-process-output with quit inhibited!!

To fix this, install the anaconda-mode anaconda-deps by hand:

pip install  jedi==0.8.1 json-rpc==1.8.1 service_factory==0.1.2

Source: https://github.com/proofit404/anaconda-mode#issues

If you are facing errors such as "Unable to run anaconda-mode server", try setting your PYTHONPATH as explained at https://github.com/proofit404/anaconda-mode#pythonpath

To enable automatic buffer formatting on save with YAPF set the variable python-enable-yapf-format-on-save to t.

(setq-default dotspacemacs-configuration-layers '(
  (python :variables python-enable-yapf-format-on-save t)))

To be able to suppress unused imports easily, install autoflake:

pip install autoflake

To use pylookup on SPC m h H, make sure you update the database first, using SPC SPC pylookup-update.

To be able to connect to an inferior lisp repl in hy-mode, you need to make sure that hy is installed.

pip install hy

A virtual environment provides isolation of your Python package versions. For a general overview see this site. Virtualenvwrapper which is also explained in the previous link, is a program which manages your virtual environments in a central location set by the WORKON_HOME environment variable.

Spacemacs integration of virtual environments and virtualenvwrapper is provided by the pyvenv package. It provides the following keybindings:

If you need multiple Python versions (e.g. Python 2 and Python 3) then take a look at pyenv. It enables the installation and managment of multiple Python versions. This blogpost gives a good overview on how to use the tool. Spacemacs integration is provided by pyenv mode which has the following keybindings.

Pyenv can also manage virtual environments for each of the Python versions it has installed. Those will be listed alongside your Python versions.

Start a Python or iPython inferior REPL process with SPC m s i. If ipython is available in system executable search paths, ipython will be used to launch python shell; otherwise, default python interpreter will be used. You may change your system executable search path by activating a virtual environment.

Send code to inferior process commands:

To run a Python script like you would in the shell press SPC m c c to start the Python script in comint mode. This is useful when working with multiple Python files since the REPL does not reload changes made in other modules.

Note: With the universal argument SPC u you can enter a new compilation command.

Test commands start with m t. To use the secondary test runner call the function with a prefix argument, for example SPC u SPC m t a.

Live coding is provided by the live-py-plugin.

Start a Hy inferior repel process with SPC m s i. If hy is available in system executable search paths, hy will be used to launch the shell. You may change your system executable search path by activating a virtual enviornment.

Send code to hy REPL commands:

If you want to customize the fill column value, use something like this inside the user-init function in your .spacemacs:

(setq-default dotspacemacs-configuration-layers '(
    (python :variables python-fill-column 99)))

If you want imports to be automatically sorted when you save a file (using isort), set the python-sort-imports-on-save variable in the python layer config section:

(setq-default dotspacemacs-configuration-layers
  '((python :variables python-sort-imports-on-save t)))

or as a directory-local variable (for per-project settings).