sideline

Show informations on the side

This library provides the frontend UI to display information either on the left/right side of the buffer window.

P.S. The implementation is extracted and modified from lsp-ui-sideline

Table of Contents

• sideline
  • ❓ Why?
  • 🔨 Quickstart
    • 👥 Configure backends
  • 📌 Define your own backend
  • ❓ FAQ
    • 💫 How to force render the sideline on the next command?
  • 📂 Example projects
  • 🛠️ Contribute
    • 🔬 Development
  • ⚜️ License

❓ Why?

Instead of hard-coded information, we extracted it to multiple different backends. It allows us to customize the displayed information we want, which is more flexible and configurable.

🔨 Quickstart

(use-package sideline
  :init
  (setq sideline-backends-left-skip-current-line t   ; don't display on current line (left)
        sideline-backends-right-skip-current-line t  ; don't display on current line (right)
        sideline-order-left 'down                    ; or 'up
        sideline-order-right 'up                     ; or 'down
        sideline-format-left "%s   "                 ; format for left aligment
        sideline-format-right "   %s"                ; format for right aligment
        sideline-priority 100                        ; overlays' priority
        sideline-display-backend-name t))            ; display the backend name

Then you enable sideline-mode depends on the backend you use. For example:

(use-package sideline
  :hook ((flycheck-mode . sideline-mode)   ; for `sideline-flycheck`
         (flymake-mode  . sideline-mode))  ; for `sideline-flymake`
  ...

Some backends require extra setup. sideline-flycheck is one of that backends:

(use-package sideline-flycheck
  :hook (flycheck-mode . sideline-flycheck-setup))

Or simply M-x sideline-mode!

👥 Configure backends

The most basic way to set up the backends for sideline.

(use-package sideline
  :init
  (setq sideline-backends-left '(sideline-flycheck)
        sideline-backends-right '(sideline-lsp)))

Alternatively, you could set it to cons cell with the search order.

(use-package sideline
  :init
  (setq sideline-backends-right '((sideline-lsp      . up)
                                  (sideline-flycheck . down))))

📌 Define your own backend

Following is an example code to define your own sideline backend:

(defun my-backend (command)
  "Example backend."
  (cl-case command
    (`candidates '("info 1" "info 2" "info 3"))  ; required
    (`action (lambda (candidate &rest _)   ; optional
               (message "Execute command for `%s`!" candidate)))))

or define it asynchronously:

(defun my-backend-async (command)
  "Example async backend."
  (cl-case command
    (`candidates (cons :async (lambda (callback &rest _)
                                (funcall callback '("info 1" "info 2" "info 3")))))
    (`action ...)))

then you can tell your user to...

(setq sideline-backends-left '(my-backend))  ; use `sideline-backends-right' for right alignment

Here is a list of supported commands:

• candidates - list of strings to display; accept async function
• action - (optional) callback function after the mouse click
• face - (optional) face overrides the default sideline face
• name - (optional) backend name to display

❓ FAQ

💫 How to force render the sideline on the next command?

You can force update sideline by adding a hook or advice with the function sideline-render-this.

(add-hook 'ts-fold-on-fold-hook #'sideline-render-this)

📂 Example projects

• sideline-blame
• sideline-flycheck
• sideline-flymake
• sideline-lsp
• sideline-eldoc
• sideline-color
• sideline-load-cost

🛠️ Contribute

If you would like to contribute to this project, you may either clone and make pull requests to this repository. Or you can clone the project and establish your own branch of this tool. Any methods are welcome!

🔬 Development

To run the test locally, you will need the following tools:

• Eask
• Make (optional)

Install all dependencies and development dependencies:

$ eask install-deps --dev

To test the package's installation:

$ eask package
$ eask install

To test compilation:

$ eask compile

🪧 The following steps are optional, but we recommend you follow these lint results!

The built-in checkdoc linter:

$ eask lint checkdoc

The standard package linter:

$ eask lint package

📝 P.S. For more information, find the Eask manual at https://emacs-eask.github.io/.

⚜️ License

This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program. If not, see https://www.gnu.org/licenses/.

See LICENSE for details.