019f8fd211
git-subtree-dir: users/wpcarro git-subtree-mainline:464bbcb15cgit-subtree-split:24f5a642afChange-Id: I6105b3762b79126b3488359c95978cadb3efa789
89 lines
2.8 KiB
EmacsLisp
89 lines
2.8 KiB
EmacsLisp
;;; cache.el --- Caching things -*- lexical-binding: t -*-
|
|
|
|
;; Author: William Carroll <wpcarro@gmail.com>
|
|
;; Version: 0.0.1
|
|
;; URL: https://git.wpcarro.dev/wpcarro/briefcase
|
|
;; Package-Requires: ((emacs "24.3"))
|
|
|
|
;;; Commentary:
|
|
;; An immutable cache data structure.
|
|
;;
|
|
;; This is like a sideways stack, that you can pull values out from and re-push
|
|
;; to the top. It'd be like a stack supporting push, pop, pull.
|
|
;;
|
|
;; This isn't a key-value data-structure like you might expect from a
|
|
;; traditional cache. The name is subject to change, but the underlying idea of
|
|
;; a cache remains the same.
|
|
;;
|
|
;; Think about prescient.el, which uses essentially an LRU cache integrated into
|
|
;; counsel to help create a "clairovoyant", self-organizing list.
|
|
;;
|
|
;; Use-cases:
|
|
;; - Keeps an cache of workspaces sorted as MRU with an LRU eviction strategy.
|
|
|
|
;;; Code:
|
|
|
|
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
|
|
;; Dependencies
|
|
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
|
|
|
|
(require 'prelude)
|
|
(require 'struct)
|
|
(require '>)
|
|
|
|
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
|
|
;; Library
|
|
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
|
|
|
|
(cl-defstruct cache xs)
|
|
|
|
;; TODO: Prefer another KBD for yasnippet form completion than company-mode's
|
|
;; current KBD.
|
|
|
|
(defun cache-from-list (xs)
|
|
"Turn list, XS, into a cache."
|
|
(make-cache :xs xs))
|
|
|
|
(defun cache-contains? (x xs)
|
|
"Return t if X in XS."
|
|
(->> xs
|
|
cache-xs
|
|
(list-contains? x)))
|
|
|
|
(defun cache-touch (x xs)
|
|
"Ensure value X in cache, XS, is front of the list.
|
|
If X isn't in XS (using `equal'), insert it at the front."
|
|
(struct-update
|
|
cache
|
|
xs
|
|
(>-> (list-reject (lambda (y) (equal x y)))
|
|
(list-cons x))
|
|
xs))
|
|
|
|
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
|
|
;; Tests
|
|
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
|
|
|
|
(progn
|
|
(let ((cache (cache-from-list '("chicken" "nugget"))))
|
|
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
|
|
;; contains?/2
|
|
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
|
|
(prelude-refute
|
|
(cache-contains? "turkey" cache))
|
|
(prelude-assert
|
|
(cache-contains? "chicken" cache))
|
|
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
|
|
;; touch/2
|
|
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
|
|
(prelude-assert
|
|
(equal
|
|
(cache-touch "nugget" cache)
|
|
(cache-from-list '("nugget" "chicken"))))
|
|
(prelude-assert
|
|
(equal
|
|
(cache-touch "spicy" cache)
|
|
(cache-from-list '("spicy" "chicken" "nugget"))))))
|
|
|
|
(provide 'cache)
|
|
;;; cache.el ends here
|