75a9a156a0
I created a strangely named Elisp module, >.el, just to appease the CI gods. My gut tells me that this is a desperate idea and fails the smell test. I'm pretty eager to pass the linting phase of my Elisp CI, however, and I can always revert this.
89 lines
2.8 KiB
EmacsLisp
89 lines
2.8 KiB
EmacsLisp
;;; cache.el --- Caching things -*- lexical-binding: t -*-
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;; Author: William Carroll <wpcarro@gmail.com>
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;; Version: 0.0.1
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;; URL: https://git.wpcarro.dev/wpcarro/briefcase
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;; Package-Requires: ((emacs "24.3"))
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;;; Commentary:
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;; An immutable cache data structure.
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;;
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;; This is like a sideways stack, that you can pull values out from and re-push
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;; to the top. It'd be like a stack supporting push, pop, pull.
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;;
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;; This isn't a key-value data-structure like you might expect from a
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;; traditional cache. The name is subject to change, but the underlying idea of
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;; a cache remains the same.
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;;
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;; Think about prescient.el, which uses essentially an LRU cache integrated into
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;; counsel to help create a "clairovoyant", self-organizing list.
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;;
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;; Use-cases:
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;; - Keeps an cache of workspaces sorted as MRU with an LRU eviction strategy.
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;;; Code:
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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;; Dependencies
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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(require 'prelude)
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(require 'struct)
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(require '>)
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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;; Library
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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(cl-defstruct cache xs)
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;; TODO: Prefer another KBD for yasnippet form completion than company-mode's
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;; current KBD.
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(defun cache-from-list (xs)
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"Turn list, XS, into a cache."
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(make-cache :xs xs))
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(defun cache-contains? (x xs)
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"Return t if X in XS."
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(->> xs
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cache-xs
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(list-contains? x)))
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(defun cache-touch (x xs)
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"Ensure value X in cache, XS, is front of the list.
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If X isn't in XS (using `equal'), insert it at the front."
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(struct-update
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cache
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xs
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(>-> (list-reject (lambda (y) (equal x y)))
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(list-cons x))
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xs))
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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;; Tests
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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(progn
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(let ((cache (cache-from-list '("chicken" "nugget"))))
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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;; contains?/2
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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(prelude-refute
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(cache-contains? "turkey" cache))
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(prelude-assert
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(cache-contains? "chicken" cache))
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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;; touch/2
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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(prelude-assert
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(equal
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(cache-touch "nugget" cache)
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(cache-from-list '("nugget" "chicken"))))
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(prelude-assert
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(equal
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(cache-touch "spicy" cache)
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(cache-from-list '("spicy" "chicken" "nugget"))))))
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(provide 'cache)
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;;; cache.el ends here
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