smart-comment

Smarter commenting for Emacs.

About

Code gets rewritten when refactoring to accomidate for new features or when fixing bugs. An approach used by many developers is to disable a piece of code with comments, then rewrite an improved version below, test that is works and then delete the commented code. smart-comment makes this and similair workflows much swifter.

smart-comment is implemented on top of the commenting functions built in to Emacs. It is meant to replace comment-dwim as the function you bind to M-;.

It triggers different comment actions taking the current location of the point into acount. Commenting out lines of code is faster. Commented lines can be marked for later deletion and then all removed with a single command.

Demonstration

Installation

Install from MELPA or put smart-comment.el somewhere in you load path.

(add-to-list 'load-path "~/emacs.d")
(require 'smart-comment)
(global-set-key (kbd "M-;") 'smart-comment)

With use-package.

(use-package smart-comment
  :bind ("M-;" . smart-comment))

Tutorial

You should have smart-comment bound to M-; or another key of your choosing. The default behaviour is described below.

Pressing M-; when the cursor is at the end of a line inserts a comment at the end of the line. This is the same as the default behaviour of M-;.

Pressing M-; when the cursor is not at the end of the line comments out the line. If a universal argument is passed the line is also marked for deletion. I.e. C-u M-; marks a line for deletion.

Passing two universal arguments, i.e. C-u C-u M-; deletes all lines marked for deletion.

smart-comment tries to be smart about what it does. For instance adding a mark to a line that is already marked will remove the mark instead.

smart-comment

smart-comment simply invokes other functions based on the cursors current position on the line.

• At the beginning a line: Calls the function referred to by smart-comment-beg-action. By default this is smart-comment-line which will comment out the current line.
• In the middle of a line: Calls the function referred to by smart-comment-mid-action. By default this is smart-comment-line as above.
• The the end of a line: Calls the function referred to by smart-comment-end-action. By default this is comment-dwim—the function Emacs binds to M-; by default.

If the region is active smart-comment calls smart-comment-region. When invoked with two universal arguments it calls smart-comment-cleanup which deletes all lines marked for deletion.

Thanks

Thanks to @limemloh for bug finding and feedback.