From 271e7f95610a91153ff2181aca33a5c70692a3fe Mon Sep 17 00:00:00 2001 From: William Carroll Date: Wed, 8 Jan 2020 15:21:37 +0000 Subject: Support functions for navigating buffer caches I've wanted an MRU/LRU sort of my "source code buffers" in Emacs. This commit support three ways for working with a cache of source code buffers. So first, what's a source code buffer? Well it isn't a buffer like *Messages*; we can call these "Emacs-generated" buffers for convenience. Other problematic buffers are buffers like `magit-status` and `dired-mode` and `erc` buffers. I added some predicates for querying buffers for their major modes. Supporting three KBDs for quickly accessing these functions: 1. Toggle previous buffer 2. b Use ivy to fuzzily search source code buffers 3. C-{f,b} Cycle {forwards,backwards} through the source code buffer cache. --- configs/shared/.emacs.d/wpc/buffer.el | 141 +++++++++++++++++++++++++++++++++- 1 file changed, 138 insertions(+), 3 deletions(-) (limited to 'configs/shared/.emacs.d/wpc/buffer.el') diff --git a/configs/shared/.emacs.d/wpc/buffer.el b/configs/shared/.emacs.d/wpc/buffer.el index 9de14b4bd4c1..ea2c5945a1b7 100644 --- a/configs/shared/.emacs.d/wpc/buffer.el +++ b/configs/shared/.emacs.d/wpc/buffer.el @@ -9,6 +9,13 @@ ;; 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: +;; 2. Using `ivy-read': b +;; TODO: These obscure evil KBDs. Maybe a hydra definition would be best? +;; 3. Cycling (forwards/backwards): C-f, C-b ;;; Code: @@ -16,20 +23,66 @@ ;; Dependencies ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; +(require 'prelude) (require 'maybe) +(require 'set) +(require 'cycle) ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ;; Library ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; -(defun buffer/exists? (name) - "Return t if buffer, NAME, exists." - (maybe/some? (buffer/find name))) +(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) + "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)) @@ -47,5 +100,87 @@ Return a reference to that buffer." "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 + (setf (source-code-cycle-cycle buffer/source-code-cycle-state) + (cycle/from-list (buffer/source-code-buffers))) + (let ((cycle (source-code-cycle-cycle + buffer/source-code-cycle-state))) + (funcall cycle-fn cycle) + (switch-to-buffer (cycle/current cycle))) + (setf (source-code-cycle-last-called buffer/source-code-cycle-state) + (ts-now))) + (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))) + +;; TODO: Replace `evil-leader/set-key' with `general-def'. +(when buffer/install-kbds? + (general-define-key + :states '(normal) + "C-f" #'buffer/cycle-next + "C-b" #'buffer/cycle-prev) + (evil-leader/set-key + "b" #'buffer/ivy-source-code + "" #'buffer/show-previous) + ) + +;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; +;; 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 -- cgit 1.4.1