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Diffstat (limited to 'emacs/.emacs.d/wpc/buffer.el')
| -rw-r--r-- | emacs/.emacs.d/wpc/buffer.el | 198 |
1 files changed, 198 insertions, 0 deletions
diff --git a/emacs/.emacs.d/wpc/buffer.el b/emacs/.emacs.d/wpc/buffer.el new file mode 100644 index 000000000000..d388818e58a4 --- /dev/null +++ b/emacs/.emacs.d/wpc/buffer.el @@ -0,0 +1,198 @@ +;;; buffer.el --- Working with Emacs buffers -*- lexical-binding: t -*- +;; Author: William Carroll <wpcarro@gmail.com> + +;;; Commentary: +;; Utilities for CRUDing buffers in Emacs. +;; +;; Many of these functions may seem unnecessary especially when you consider +;; there implementations. In general I believe that Elisp suffers from a +;; library disorganization problem. Providing simple wrapper functions that +;; rename functions or reorder parameters is worth the effort in my opinion if +;; it improves discoverability (via intuition) and improve composability. +;; +;; I support three ways for switching between what I'm calling "source code +;; buffers": +;; 1. Toggling previous: <SPC><SPC> +;; 2. Using `ivy-read': <SPC>b +;; TODO: These obscure evil KBDs. Maybe a hydra definition would be best? +;; 3. Cycling (forwards/backwards): C-f, C-b + +;;; Code: + +;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; +;; Dependencies +;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; + +(require 'prelude) +(require 'maybe) +(require 'set) +(require 'cycle) +(require 'struct) + +;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; +;; Library +;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; + +(defconst buffer/enable-tests? t + "When t, run the test suite.") + +(defconst buffer/install-kbds? t + "When t, install the keybindings defined herein.") + +(defconst buffer/source-code-blacklist + (set/new 'dired-mode + 'erc-mode + 'magit-status-mode + 'magit-process-mode + 'magit-log-mode + 'org-mode + 'fundamental-mode) + "A blacklist of major-modes to ignore for listing source code buffers.") + +(defconst buffer/source-code-timeout 2 + "Number of seconds to wait before invalidating the cycle.") + +(cl-defstruct source-code-cycle cycle last-called) + +(defun buffer/emacs-generated? (name) + "Return t if buffer, NAME, is an Emacs-generated buffer. +Some buffers are Emacs-generated but are surrounded by whitespace." + (let ((trimmed (s-trim name))) + (and (s-starts-with? "*" trimmed)))) + +(defun buffer/find (buffer-or-name) + "Find a buffer by its BUFFER-OR-NAME." + (get-buffer buffer-or-name)) + +(defun buffer/major-mode (name) + "Return the active `major-mode' in buffer, NAME." + (with-current-buffer (buffer/find name) + major-mode)) + +(defun buffer/source-code-buffers () + "Return a list of source code buffers. +This will ignore Emacs-generated buffers, like *Messages*. It will also ignore + any buffer whose major mode is defined in `buffer/source-code-blacklist'." + (->> (buffer-list) + (list/map #'buffer-name) + (list/reject #'buffer/emacs-generated?) + (list/reject (lambda (name) + (set/contains? (buffer/major-mode name) + buffer/source-code-blacklist))))) + +(defvar buffer/source-code-cycle-state + (make-source-code-cycle + :cycle (cycle/from-list (buffer/source-code-buffers)) + :last-called (ts-now)) + "State used to manage cycling between source code buffers.") + +(defun buffer/exists? (name) + "Return t if buffer, NAME, exists." + (maybe/some? (buffer/find name))) + +(defun buffer/new (name) + "Return a newly created buffer NAME." + (generate-new-buffer name)) + +(defun buffer/find-or-create (name) + "Find or create buffer, NAME. +Return a reference to that buffer." + (let ((x (buffer/find name))) + (if (maybe/some? x) + x + (buffer/new name)))) + +;; TODO: Should this consume: `display-buffer' or `switch-to-buffer'? +(defun buffer/show (buffer-or-name) + "Display the BUFFER-OR-NAME, which is either a buffer reference or its name." + (display-buffer buffer-or-name)) + +;; TODO: Move this and `buffer/cycle-prev' into a separate module that +;; encapsulates all of this behavior. + +(defun buffer/cycle (cycle-fn) + "Cycle forwards or backwards through `buffer/source-code-buffers'." + (let ((last-called (source-code-cycle-last-called + buffer/source-code-cycle-state)) + (cycle (source-code-cycle-cycle + buffer/source-code-cycle-state))) + (if (> (ts-diff (ts-now) last-called) + buffer/source-code-timeout) + (progn + (struct/set! source-code-cycle + cycle + (cycle/from-list (buffer/source-code-buffers)) + buffer/source-code-cycle-state) + (let ((cycle (source-code-cycle-cycle + buffer/source-code-cycle-state))) + (funcall cycle-fn cycle) + (switch-to-buffer (cycle/current cycle))) + (struct/set! source-code-cycle + last-called + (ts-now) + buffer/source-code-cycle-state)) + (progn + (funcall cycle-fn cycle) + (switch-to-buffer (cycle/current cycle)))))) + +(defun buffer/cycle-next () + "Cycle forward through the `buffer/source-code-buffers'." + (interactive) + (buffer/cycle #'cycle/next)) + +(defun buffer/cycle-prev () + "Cycle backward through the `buffer/source-code-buffers'." + (interactive) + (buffer/cycle #'cycle/prev)) + +(defun buffer/ivy-source-code () + "Use `ivy-read' to choose among all open source code buffers." + (interactive) + (ivy-read "Source code buffer: " + (-drop 1 (buffer/source-code-buffers)) + :sort nil + :action #'switch-to-buffer)) + +(defun buffer/show-previous () + "Call `switch-to-buffer' on the previously visited buffer. +This function ignores Emacs-generated buffers, i.e. the ones that look like + this: *Buffer*. It also ignores buffers that are `dired-mode' or `erc-mode'. + This blacklist can easily be changed." + (interactive) + (let* ((xs (buffer/source-code-buffers)) + (candidate (list/get 1 xs))) + (prelude/assert (maybe/some? candidate)) + (switch-to-buffer candidate))) + +(when buffer/install-kbds? + (general-define-key + :states '(normal) + "C-f" #'buffer/cycle-next + "C-b" #'buffer/cycle-prev) + (general-define-key + :prefix "<SPC>" + :states '(normal) + "b" #'buffer/ivy-source-code + "<SPC>" #'buffer/show-previous + "k" #'kill-buffer)) + +;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; +;; Tests +;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; + +(when buffer/enable-tests? + (prelude/assert + (list/all? #'buffer/emacs-generated? + '("*scratch*" + "*Messages*" + "*shell*" + "*Shell Command Output*" + "*Occur*" + "*Warnings*" + "*Help*" + "*Completions*" + "*Apropos*" + "*info*")))) + +(provide 'buffer) +;;; buffer.el ends here |