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Diffstat (limited to 'users/wpcarro/emacs/.emacs.d/wpc/buffer.el')
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1 files changed, 173 insertions, 0 deletions
diff --git a/users/wpcarro/emacs/.emacs.d/wpc/buffer.el b/users/wpcarro/emacs/.emacs.d/wpc/buffer.el new file mode 100644 index 0000000000..fa98393df8 --- /dev/null +++ b/users/wpcarro/emacs/.emacs.d/wpc/buffer.el @@ -0,0 +1,173 @@ +;;; buffer.el --- Working with buffers -*- lexical-binding: t -*- + +;; Author: William Carroll <wpcarro@gmail.com> +;; Version: 0.0.1 +;; Package-Requires: ((emacs "24.3")) + +;;; 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) +(require 'ts) +(require 'general) + +;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; +;; Library +;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; + +(defconst buffer-source-code-blacklist + (set-new 'dired-mode + 'erc-mode + 'vterm-mode + 'magit-status-mode + 'magit-process-mode + 'magit-log-mode + 'magit-diff-mode + 'org-mode + 'fundamental-mode) + "A blacklist of major-modes to ignore for listing source code buffers.") + +(defconst buffer-ivy-source-code-whitelist '("*scratch*" "*Messages*") + "A whitelist of buffers to include when 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) + "Using CYCLE-FN, move 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: " + (-concat buffer-ivy-source-code-whitelist + (-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))) + +(provide 'buffer) +;;; buffer.el ends here |