RedBaron4emacs

POC for python code manipulation with a Full Syntax Tree. That’s better than regexps.

RedBaron: https://redbaron.readthedocs.org/en/latest/tuto.html

Install

This library is based on RedBaron:

pip install redbaron

You need hydra.el (in Melpa, that’s optionnal but real handy) and helm (for helm-imenu).

For the moment, clone this repository and load red4emacs.el. Doing so will set the path to the python code that lives alongside it (see red4emacs-path).

Usage

The one command to know to see all options:

M-x red4e-hydra/body

Another example, renaming an argument and its occurences inside the method body:

Add an argument

Inside a function, call M-x red4e-add-arg RET whatever RET. It replaces the method definition with a new one.

It respects args on many lines (well it isn’t that clever, it’s all in one line or each on its line).

Add *args and **kwargs

There is a shortcut to add those two special args quickly: * on the hydra and otherwise M-x red4e-add-args-kwargs.

Rename an argument

M-x red4e-rename-arg

Renaming an argument will ask you to search and replace it inside the method body.

Current method: rename (in project), kill, comment, copy

The actions for the current method are grouped under the hydra red4e-hydra-method/body, accessible from the main hydra.

We can rename the current methode, just once or in the current project (using projectile), and kill, comment or copy it.

M-x red4e-rename-method

or

M-x red4e-rename-method-in-project

The second choice will ask you to search and replace this method in the current project (based on projectile’s projectile-replace).

Write args in one line or in multiple lines

M-x red4e-args-multi-line-toggle

or l on the hydra (“lines”).

Note: see also multi-line and fillcode.

Move around defs with imenu

The hydra has the i binding to call imenu, so you can jump to another def and carry on using red4e.

As an imenu frontend, you can stick with the default and very basic prompt (completing-read), or choose between helm and ivy:

(setq red4e-selection-method 'red4e-selection-ivy)
(setq red4e-selection-method 'red4e-selection-helm)

Rename a symbol inside the current defun

S in the hydra. It’s a simple search and replace inside the method body.

Add and remove a decorator

You can add a decorator to the current method:

M-x red4e-decorator-add

Or @ with the hydra.

It will suggest a list of decorators used in the current buffer. As usual, you can bypass the ido prompt with C-f and type another one. In that case, you can omit the “@”.

If we choose “@staticmethod”, then it removes “self” from the method signature.

This function doesn’t use the redbaron python library.

Thus the remove (D with the hydra) only works with one-line decorators.

Motivation

take the string def foo(first, **kwargs, second=foo): pass, where the arguments are in a bad order, and sort them:

def foo(first, second=foo, **kwargs): pass

Call that from within emacs, use with my snippet to add an argument to a function, and it becomes a bit simpler (no more movements around the code) and smarter (we manipulate code, not text with clunky regexps) to add an argument to a method.

See also

• emacs-traad for real refactoring (using Rope) and straightforward installation.