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Diffstat (limited to 'users/wpcarro/emacs/.emacs.d/wpc/bag.el')
-rw-r--r-- | users/wpcarro/emacs/.emacs.d/wpc/bag.el | 70 |
1 files changed, 0 insertions, 70 deletions
diff --git a/users/wpcarro/emacs/.emacs.d/wpc/bag.el b/users/wpcarro/emacs/.emacs.d/wpc/bag.el deleted file mode 100644 index 467e25fceb65..000000000000 --- a/users/wpcarro/emacs/.emacs.d/wpc/bag.el +++ /dev/null @@ -1,70 +0,0 @@ -;;; bag.el --- Working with bags (aka multi-sets) -*- lexical-binding: t -*- - -;; Author: William Carroll <wpcarro@gmail.com> -;; Version: 0.0.1 -;; Package-Requires: ((emacs "24.3")) - -;;; Commentary: -;; What is a bag? A bag should be thought of as a frequency table. It's a way -;; to convert a list of something into a set that allows duplicates. Isn't -;; allowing duplicates the whole thing with Sets? Kind of. But the interface -;; of Sets is something that bags resemble, so multi-set isn't as bag of a name -;; as it may first seem. -;; -;; If you've used Python's collections.Counter, the concept of a bag should be -;; familiar already. -;; -;; Interface: -;; - add :: x -> Bag(x) -> Bag(x) -;; - remove :: x -> Bag(x) -> Bag(x) -;; - union :: Bag(x) -> Bag(x) -> Bag(x) -;; - difference :: Bag(x) -> Bag(x) -> Bag(x) - -;;; Code: - -;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; -;; Dependencies -;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; - -(require 'al) -(require 'number) - -;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; -;; Library -;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; - -(cl-defstruct bag xs) - -(defun bag-update (f xs) - "Call F on alist in XS." - (let ((ys (bag-xs xs))) - (setf (bag-xs xs) (funcall f ys)))) - -(defun bag-new () - "Create an empty bag." - (make-bag :xs (al-new))) - -(defun bag-contains? (x xs) - "Return t if XS has X." - (al-has-key? x (bag-xs xs))) - -;; TODO: Tabling this for now since working with structs seems to be -;; disappointingly difficult. Where is `struct-update'? -;; (defun bag-add (x xs) -;; "Add X to XS.") - -;; TODO: What do we name delete vs. remove? -;; (defun bag-remove (x xs) -;; "Remove X from XS. -;; This is a no-op is X doesn't exist in XS.") - -(defun bag-from-list (xs) - "Map a list of `XS' into a bag." - (->> xs - (list-reduce - (bag-new) - (lambda (x acc) - (bag-add x 1 #'number-inc acc))))) - -(provide 'bag) -;;; bag.el ends here |