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Diffstat (limited to 'configs/shared/.emacs.d/wpc/cycle.el')
-rw-r--r-- | configs/shared/.emacs.d/wpc/cycle.el | 155 |
1 files changed, 0 insertions, 155 deletions
diff --git a/configs/shared/.emacs.d/wpc/cycle.el b/configs/shared/.emacs.d/wpc/cycle.el deleted file mode 100644 index 9475ddd99659..000000000000 --- a/configs/shared/.emacs.d/wpc/cycle.el +++ /dev/null @@ -1,155 +0,0 @@ -;;; cycle.el --- Simple module for working with cycles. -*- lexical-binding: t -*- -;; Author: William Carroll <wpcarro@gmail.com> - -;;; Commentary: -;; Something like this may already exist, but I'm having trouble finding it, and -;; I think writing my own is a nice exercise for learning more Elisp. - -;;; Code: - -;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; -;; Dependencies -;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; - -(require 'prelude) -(require 'math) -(require 'maybe) - -;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; -;; Wish list -;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; - -;; - TODO: Provide immutable variant. -;; - TODO: Replace mutable consumption with immutable variant. -;; - TODO: Replace indexing with (math/mod current cycle). - -;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; -;; Library -;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; - -;; `current-index' tracks the current index -;; `xs' is the original list -(cl-defstruct cycle current-index previous-index xs) - -(defconst cycle/enable-tests? t - "When t, run the tests defined herein.") - -(defun cycle/new (&rest xs) - "Create an empty cycle." - (make-cycle :current-index 0 - :previous-index nil - :xs xs)) - -(defun cycle/from-list (xs) - "Create a cycle from a list of `XS'." - (make-cycle :current-index 0 - :previous-index nil - :xs xs)) - -(defun cycle/to-list (xs) - "Return the list representation of a cycle, XS." - (cycle-xs xs)) - -(defun next-index<- (lo hi x) - "Return the next index in a cycle when moving downwards. -- `LO' is the lower bound. -- `HI' is the upper bound. -- `X' is the current index." - (if (< (- x 1) lo) - (- hi 1) - (- x 1))) - -(defun next-index-> (lo hi x) - "Return the next index in a cycle when moving upwards. -- `LO' is the lower bound. -- `HI' is the upper bound. -- `X' is the current index." - (if (>= (+ 1 x) hi) - lo - (+ 1 x))) - -(defun cycle/previous-focus (cycle) - "Return the previously focused entry in CYCLE." - (let ((i (cycle-previous-index cycle))) - (if (maybe/some? i) - (nth i (cycle-xs cycle)) - nil))) - -;; TODO: Consider adding "!" to the function name herein since many of them -;; mutate the collection, and the APIs are beginning to confuse me. -(defun cycle/focus-previous! (xs) - "Jump to the item in XS that was most recently focused; return the cycle. -This will error when previous-index is nil. This function mutates the -underlying struct." - (let ((i (cycle-previous-index xs))) - (if (maybe/some? i) - (progn - (cycle/jump i xs) - (cycle/current xs)) - (error "Cannot focus the previous element since cycle-previous-index is nil")))) - -(defun cycle/next (xs) - "Return the next value in `XS' and update `current-index'." - (let* ((current-index (cycle-current-index xs)) - (next-index (next-index-> 0 (cycle/count xs) current-index))) - (struct/set! cycle previous-index current-index xs) - (struct/set! cycle current-index next-index xs) - (nth next-index (cycle-xs xs)))) - -(defun cycle/prev (xs) - "Return the previous value in `XS' and update `current-index'." - (let* ((current-index (cycle-current-index xs)) - (next-index (next-index<- 0 (cycle/count xs) current-index))) - (struct/set! cycle previous-index current-index xs) - (struct/set! cycle current-index next-index xs) - (nth next-index (cycle-xs xs)))) - -(defun cycle/current (cycle) - "Return the current value in `CYCLE'." - (nth (cycle-current-index cycle) (cycle-xs cycle))) - -(defun cycle/count (cycle) - "Return the length of `xs' in `CYCLE'." - (length (cycle-xs cycle))) - -(defun cycle/jump (i xs) - "Jump to the I index of XS." - (let ((current-index (cycle-current-index xs)) - (next-index (math/mod i (cycle/count xs)))) - (struct/set! cycle previous-index current-index xs) - (struct/set! cycle current-index next-index xs)) - xs) - -(defun cycle/focus (p cycle) - "Focus the element in CYCLE for which predicate, P, is t." - (let ((i (->> cycle - cycle-xs - (-find-index p)))) - (if i - (cycle/jump i cycle) - (error "No element in cycle matches predicate")))) - -(defun cycle/contains? (x xs) - "Return t if cycle, XS, has member X." - (->> xs - cycle-xs - (list/contains? x))) - -;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; -;; Tests -;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; - -(when cycle/enable-tests? - (let ((xs (cycle/new 1 2 3))) - (prelude/assert (maybe/nil? (cycle/previous-focus xs))) - (prelude/assert (= 1 (cycle/current xs))) - (prelude/assert (= 2 (cycle/next xs))) - (prelude/assert (= 1 (cycle/previous-focus xs))) - (prelude/assert (= 1 (->> xs (cycle/jump 0) cycle/current))) - (prelude/assert (= 2 (->> xs (cycle/jump 1) cycle/current))) - (prelude/assert (= 3 (->> xs (cycle/jump 2) cycle/current))) - (prelude/assert (= 2 (cycle/previous-focus xs))) - (prelude/assert (= 2 (cycle/focus-previous! xs))))) - -(provide 'cycle) -;;; cycle.el ends here |