Tag Archives: outline-minor-mode

outline-indent – Indentation based Folding and Outlining in Emacs

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The outline-indent Emacs package provides a minor mode that enables code folding and outlining based on indentation levels for various indentation-based text files, such as YAML, Python, and other indented text files.

In addition to code folding, outline-indent allows moving indented sub-trees up and down, promoting and demoting sections to adjust indentation levels, customizing the ellipsis, and inserting a new line with the same indentation level as the current line, among other features.

The outline-indent package leverages the built-in outline-minor-mode, which is maintained by the Emacs developers and has less chance of being abandoned like origami.el.

The outline-indent Emacs package offers a similar functionality to Vim’s set foldmethod=indent setting. Just as in Vim, it allows to fold and unfold code sections based on their indentation levels.

Installation

To install the outline-indent from MELPA:

  1. If you haven’t already done so, add MELPA repository to your Emacs configuration.
  2. Add the following code to your Emacs init file to install the outline-indent package from MELPA:
(use-package outline-indent
  :ensure t
  :custom
  (outline-indent-ellipsis " ▼ "))Code language: Lisp (lisp)

More information about outline-indent

Emacs: Enhancing up and down subtree movement in outline-mode and outline-minor-mode

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When editing outlined files (e.g., using the built-in outline-minor-mode, or packages like outline-indent.el, outline-yaml.el, etc.), handling subtrees efficiently can significantly enhance productivity, especially when working with complex documents. If you’re familiar with outline-mode or outline-minor-mode, you might have noticed that the built-in functions for moving subtrees up and down, outline-move-subtree-up and outline-move-subtree-down:

  • Blank line exclusion: outline-move-subtree-up and outline-move-subtree-down exclude the last blank line of the subtree when the outline-blank-line variable is set to t. Setting outline-blank-line to t is worthwhile because it retains a visible blank line after the subtree and before the next heading, improving the readability of the document.
  • Cursor position reset: After moving a subtree up or down, the cursor position is often reset, which can be disruptive during editing.

Here’s how you can address these issues by using custom functions to enhance subtree movement:

(require 'outline)

(defun my-advice-outline-hide-subtree (orig-fun &rest args)
  "Advice for `outline-hide-subtree'.
This ensures that the outline is folded correctly by
outline-move-subtree-up/down, preventing it from being unable to open the fold."
  (let ((outline-blank-line
         (if (bound-and-true-p my-outline-hide-subtree-blank-line-enabled)
             my-outline-hide-subtree-blank-line
           outline-blank-line)))
    (apply orig-fun args)))

(defun my-advice-outline-move-subtree-up-down (orig-fun &rest args)
  "Move the current subtree up/down past ARGS headlines of the same level.
This function ensures the last blank line is included, even when
`outline-blank-line' is set to t. It also restores the cursor position,
addressing the issue where the cursor might be reset after the operation."
  (interactive "p")
  (let ((column (current-column))
        (outline-blank-line nil)
        (my-outline-hide-subtree-blank-line-enabled t)
        (my-outline-hide-subtree-blank-line outline-blank-line))
    (apply orig-fun (or args 1))
    (move-to-column column)))

(advice-add 'outline-hide-subtree
            :around #'my-advice-outline-hide-subtree)
(advice-add 'outline-move-subtree-up
            :around #'my-advice-outline-move-subtree-up-down)
(advice-add 'outline-move-subtree-down
            :around #'my-advice-outline-move-subtree-up-down)Code language: Lisp (lisp)

I also recommend using Ctrl-Up and Ctrl-Down key bindings for moving subtrees up and down.

(define-key outline-mode-map (kbd "C-<up>") 'outline-move-subtree-up)
(define-key outline-mode-map (kbd "C-<down>") 'outline-move-subtree-down)

(defun my-setup-outline-minor-mode-keybindings ()
    "Set up keybindings for moving subtrees in `outline-minor-mode'."
  (define-key outline-minor-mode-map (kbd "C-<up>") 'outline-move-subtree-up)
  (define-key outline-minor-mode-map (kbd "C-<down>") 'outline-move-subtree-down))
(add-hook 'outline-minor-mode-hook 'my-setup-outline-minor-mode-keybindings) Code language: Lisp (lisp)

With this setup, you will ensure that every time you use outline-move-subtree-up or outline-move-subtree-down, the last blank line of the subtree is included and the cursor position is restored.